High performance cable connector assembly

ABSTRACT

Connector assemblies that may be used to connect a cable to one or more contact tails of an electrical connector are disclosed. Some connector assemblies may include a wire extending from a cable and attached to an edge of a contact tail of a signal conductor. At least a portion of the wire may be flattened to form a planar surface that is attached to a corresponding planar surface of the edge of the contact tail. Moreover, some connector assemblies may include a wire extending from a cable that is attached to an edge of a contact tail via a metallurgical bond extending along at least a portion of an attachment interface between the wire and the contact tail.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 62/809,381, filed on Feb. 22, 2019, entitled “HIGH PERFORMANCE CABLE CONNECTOR ASSEMBLY,” which is hereby incorporated herein by reference in its entirety.

BACKGROUND

This patent application relates generally to interconnection systems, such as those including cables and electrical connectors.

Cables are used in many electronic systems. Electronic systems are assembled from multiple components that are interconnected. Often, components are mounted to printed circuit boards (PCBs), which provide both mechanical support for the components and conductive structures that deliver power to the components and provide signal paths between components attached to the PCB.

Sometimes PCBs are joined together with electrical connectors. The connectors provide a separable interface such that the PCBs in a system can be manufactured at different times or in different locations, yet simply assembled into a system. A known arrangement for joining several printed circuit boards is to have one printed circuit board serve as a backplane. Other printed circuit boards, called “daughterboards” or “daughtercards,” may be connected through the backplane.

A backplane is a printed circuit board onto which many connectors may be mounted. Conducting traces in the backplane may be electrically connected to signal conductors in the connectors so that signals may be routed between the connectors. Daughtercards may also have connectors mounted thereon. The connectors mounted on a daughtercard may be plugged into the connectors mounted on the backplane. In this way, signals may be routed among the daughtercards through the backplane.

Connectors may also be used in other configurations for interconnecting printed circuit boards. Sometimes, one or more smaller printed circuit boards may be connected to another larger printed circuit board. In such a configuration, the larger printed circuit board may be called a “motherboard” and the printed circuit boards connected to it may be called daughterboards. Also, boards of the same size or similar sizes may sometimes be aligned in parallel. Connectors used in these applications are often called “stacking connectors” or “mezzanine connectors.”

In some scenarios, components may be separated by a longer distance than can be connected via traces in a PCB. Cables may be used to route signals between components because cables can be routed through curving paths where it would be difficult to install a rigid PCB or can be manufactured with less signal loss per inch than a PCB.

Cables provide signal paths with high signal integrity, particularly for high frequency signals, such as those above 40 Gbps using an NRZ protocol. Each cable has one or more signal conductors, which is surrounded by a dielectric material, which in turn is surrounded by a conductive layer. A protective jacket, often made of plastic, may surround these components. Additionally the jacket or other portions of the cable may include fibers or other structures for mechanical support.

One type of cable, referred to as a “twinax cable,” is constructed to support transmission of a differential signal and has a balanced pair of signal wires, is embedded in a dielectric, and encircled by a conductive layer. The conductive layer is usually formed using foil, such as aluminized Mylar. The twinax cable can also have a drain wire. Unlike a signal wire, which is generally surrounded by a dielectric, the drain wire may be uncoated so that it contacts the conductive layer at multiple points over the length of the cable.

Cables may be terminated with connectors, forming a cable assembly. The connectors may plug into mating connectors that are in turn connected to the components to be connected. At an end of the cable, where the cable is to be terminated to a connector or other terminating structure, the protective jacket, dielectric and the foil may be removed, leaving portions of the signal wires and the drain wire exposed at the end of the cable. These wires may be attached to a connector or other terminating structure. The signal wires may be attached to conductive elements serving as mating contacts in the connector. The drain wire may be attached to a ground conductor in the terminating structure. In this way, any ground return path may be continued from the cable to the terminating structure.

To receive the connector of a cable assembly, a connector, called an “I/O connector” may be mounted to a PCB, usually at an edge of the PCB. That connector may be configured to receive a plug at one end of a cable assembly, such that the cable is connected to the PCB through the I/O connector. The other end of the cable assembly may be connected to another electronic device.

Cables have also been used to make connections within the same electronic device. For example, cables have been used to route signals from an I/O connector to a processor assembly that is located at the interior of the PCB, away from the edge at which the I/O connector is mounted. In other configurations, both ends of a cable may be connected to the same PCB. The cables can be used to carry signals between components mounted to the PCB near where each end of the cable connects to the PCB.

SUMMARY

Aspects described herein relate to low loss interconnection systems.

In one aspect, some embodiments may relate to a connector assembly comprising a first signal conductor having a first contact tail and a first wire extending from a cable. The first contact tail includes an edge having a first planar surface, and a portion of the first wire is at least partially flattened to form a second planar surface. The first wire is attached to the edge of the first contact tail with the second planar surface of the first wire in contact with the first planar surface of the first contact tail.

In another aspect, some embodiments may relate to a connector assembly comprising a signal conductor having a contact tail, the contact tail comprising an edge, and wire extending from a cable and attached to the edge of the contact tail via a bond extending along an attachment interface. At least a portion of the bond is a metallurgical bond.

In a further aspect, some embodiments may relate to a method of forming an electrical connector. The method comprises bonding a wire of a cable to an edge of contact tail of a signal conductor along an attachment interface, at least in part, by melting a first material, flowing the first material into the attachment interface, and interdiffusing at least a portion of the first material and a second material across the attachment interface to form a metallurgical bond.

In yet another aspect, some embodiments may relate to a method of forming an electrical connector comprising deforming a portion of a first wire of a cable to form a first planar surface. The method further comprises attaching the first wire to an edge of a first contact tail of a first signal conductor, at least in part, by contacting the first planar surface of the first wire to a second planar surface of the edge of the first contact tail.

The foregoing is provided by way of illustration and is not intended to be limiting.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

FIG. 1 is an isometric view of an illustrative electrical interconnection system, according to some embodiments;

FIG. 2 is an isometric view, partially exploded, of the connector of FIG. 1, according to some embodiments;

FIG. 3 is an isometric view of a wafer assembly of the connector of FIG. 2, according to some embodiments;

FIG. 4 is an isometric view of wafer modules of the wafer assembly of FIG. 3, according to some embodiments;

FIG. 5 is an isometric view of a portion of the insulative housing of the wafer assembly of FIG. 3, according to some embodiments;

FIG. 6 is an isometric view, partially exploded, of a wafer module of the wafer assembly of FIG. 3, according to some embodiments;

FIG. 7 is an isometric view, partially exploded, of a portion of a wafer module of the wafer assembly of FIG. 3, according to some embodiments;

FIG. 8 is an isometric view, partially exploded, of a portion of a wafer module of the wafer assembly of FIG. 3, according to some embodiments;

FIG. 9 is an isometric view of an extender module, according to some embodiments;

FIG. 10A is an isometric view of a portion of the extender module of FIG. 9, according to some embodiments;

FIG. 10B is an isometric view of a portion of the extender module of FIG. 9, according to some embodiments;

FIG. 10C is an isometric view of a portion of the extender module of FIG. 9, according to some embodiments;

FIG. 11 is an isometric view, partially exploded, of the extender module of FIG. 11, according to some embodiments;

FIG. 12 is an isometric view of two extender modules, oriented with 180 degree rotation, according to some embodiments;

FIG. 13A is an isometric view of an assembly of the two extender modules of FIG. 12, according to some embodiments;

FIG. 13B is a schematic representation of one end of the assembly of FIG. 13A taken along line B-B, according to some embodiments;

FIG. 13C is a schematic representation of one end of the assembly of FIG. 13A taken along line C-C, according to some embodiments;

FIG. 14 is an isometric view of a connector and the assembly of extender modules of FIG. 13A, according to some embodiments;

FIG. 15A is an isometric view of an extender shell, according to some embodiments;

FIG. 15B is a perspective view, partially cut away, of the extender shell of FIG. 15A, according to some embodiments;

FIG. 16A is an isometric view, partially exploded, of an orthogonal connector, according to some embodiments;

FIG. 16B is an isometric view of an assembled orthogonal connector, according to some embodiments;

FIG. 17 is a cross-sectional view of the orthogonal connector of FIG. 16B, according to some embodiments;

FIG. 18 is an isometric view of a portion of the orthogonal connector of FIG. 16B, according to some embodiments;

FIG. 19 is an isometric view, partially exploded, of an electronic system including the orthogonal connector of FIG. 16B and the connector of FIG. 2, according to some embodiments;

FIG. 20A is an isometric view of a connector of an electrical interconnection system, showing a mating interface of a connector, according to some embodiments;

FIG. 20B is an isometric view of the connector of FIG. 20A, showing a mounting interface of the connector, according to some embodiments;

FIGS. 21A-21C are isometric views, partially exploded, of the connector of FIG. 20A, according to some embodiments;

FIG. 21D is an isometric view of connector units of the connector of FIG. 23A, according to some embodiments;

FIG. 21E is an isometric view of connector units of the connector of FIG. 23B, according to some embodiments;

FIG. 22A is an isometric view of a cable assembly, according to some embodiments;

FIG. 22B is an isometric view, partially cutaway, of the cable assembly in FIG. 22A, according to some embodiments;

FIG. 22C is an isometric view of a cable assembly module, which can be used to form the cable assembly in FIG. 22A, according to some embodiments;

FIG. 23A is an isometric view of a pair of signal conductors, according to some embodiments;

FIG. 23B is an isometric view of a cable attached to the pair of signal conductors of FIG. 23A, according to some embodiments;

FIG. 24A is a plan view of a mounting interface between a pair of signal conductors and a cable, according to some embodiments;

FIG. 24B is an elevation view of the mounting interface between the pair of signal conductors and the cable of FIG. 24A, according to some embodiments;

FIG. 24C is a plan view of a mounting interface between a pair of signal conductors and a cable, according to some embodiments;

FIG. 24D is an elevation view of the mounting interface between the pair of signal conductors and the cable of FIG. 24C, according to some embodiments;

FIG. 25A is an isometric view of a cable attached to a pair of signal conductors, according to some embodiments;

FIG. 25B is a cross-sectional view taken along line B-B of FIG. 25A;

FIG. 25C shows the cross-sectional view of FIG. 25B after deforming a signal conductor, according to some embodiments;

FIG. 26A is a cress-sectional view of an attachment interface between a signal conductor and a contact tail, according to some embodiments;

FIG. 26B shows the attachment interface of FIG. 26A after forming a metallurgical bond, according to some embodiments;

FIG. 27A shows a copper-nickel phase diagram, and illustrates an example of a material system exhibiting soluble behavior, according to some embodiments;

FIG. 27B shows a copper-silver phase diagram, and illustrates an example of a eutectic material system, according to some embodiments; and

FIG. 27 C shows a silver-nickel phase diagram, and illustrates an example of a material system exhibiting insoluble behavior, according to some embodiments.

DETAILED DESCRIPTION

The inventors have recognized and appreciated techniques for improving the performance of an electronic system through the use of low loss interconnects, particularly for high frequency signals that are enabled by the manner in which cables are attached to conductive elements in connectors or other terminating structures. In some embodiments, a pair of signal conductors of a cable (e.g., wires in the cable) may be reliably attached at opposed edges of conductive elements of a connector configured to carry a differential pair signal. With such an arrangement, changes of geometry at the cable attachment interface, which might otherwise cause changes of impedance that could impact signal integrity, may be reduced. Alternatively or additionally, such an attachment interface may reduce the amount of metal at the attachment interface, reducing the change of inductance relative to a convention design in which a cable is soldered on a broadside of a signal conductor, which also reduces changes of impedance.

The inventors have recognized and appreciated techniques that enable robust attachment of wires at an edge of conductive element. One such technique may include adjusting a shape of at least a portion of a signal conductor of a cable prior to attaching the signal conductor to a conductive element of a connector, such as a contact tail. In particular, the inventors have recognized that the typical round shape of a wire in a cable may result in a limited contact area between the wire and the conductive element of the connector, which may lead to poor quality attachment of the wire to the connector and/or undesirable impedance changes at the attachment interface as a result of the mass of material required to form a suitable attachment.

According to some aspects described herein, a wire may be deformed prior to joining with an associated conductive element of a connector such that at least a portion of the wire is at least partially flattened. The flattened portion of the wire may form a planar surface that may be placed into contact with a corresponding planar surface of the conductive element of the connector, and the wire and conductive element may subsequently be joined to attach the wire to the connector. In some embodiments, an area of the flattened portion of the wire (i.e., the planar surface of the wire) may substantially match a corresponding contact area on the conductive element of the connector (i.e., the planar surface of the conductive element), which may aid in avoiding changes in impedance through the attachment interface. For example, the wire may initially have a diameter that is larger than a thickness of the conductive element of the connector, and after flattening, the thickness of the flattened portion of the wire may substantially match the thickness of the conductive element. In some embodiments, the wire may be pressed against the contact area on the conductive element during attachment to achieve the above-described deformation of the wire. However, it should be understood that the wire may be deformed or flattened in any suitable manner, such as by flattening the wire with appropriate tooling, as the current disclosure is not limited in this regard.

Another such technique may involve forming an attachment interface and physically bonding and/or joining a wire of a cable to a conductive portion of a connector (e.g., a contact tail) with a small volume of conductive material. As noted above, changes of geometry at the cable attachment interface may lead to undesirable changes of impedance that may impact signal integrity. Accordingly, techniques described herein may reduce or eliminate such changes in geometry, for example, by forming a bond at the attachment interface without requiring solder or other material to be added to the attachment interface that may cause such geometry changes. In some embodiments, the wires of a cable and contact tails of a connector may comprise materials selected to provide desired material properties (e.g., thermodynamic and/or kinetic properties), which may facilitate joining of the wire to the conductive portion without the need for solder or other joining material. For example, the materials may be selected to form a metallurgical bond along at least a portion of the attachment interface upon heating of the attachment interface. As described in more detail below, in some instances, the heating required to form the metallurgical bond may be less than may be required for other conventional joining techniques, such as welding. Moreover, the inventors have recognized and appreciated that such lower heating requirements to form a bond may, in some instances, avoid undesirable loss of material at the attachment interface that may occur due to ablation or other effects associated with higher power joining operations, such as high power laser welding.

In some embodiments, at least a portion of the wires of a cable and/or the contact tails of a connector may comprise a coating selected to provide the above-described material properties, which may facilitate joining of the wires to the contact tails. For example, such coatings may be selected such that the coating material is soluble in a base alloy of the wire and/or contact tail, to promote interdiffusion of the materials of the wire and/or the contact tail, and/or to facilitate melting and flow of material into the attachment interface between the wire and the contact tail at lower temperatures. As used herein, a first material being soluble within a second material refers a two (or more) component material system in which the two (or more) materials form a single phase mixture at equilibrium conditions when the two (or more) materials are combined. For example, materials that are fully soluble in one another (e.g., copper and nickel; see FIG. 27A) form a single phase solid solution at temperatures below the melting point of the lower melting point material, and a single phase liquid solution at higher temperatures (i.e., above the melting point of the higher melting point material. At intermediate temperatures between the melting temperatures of the two materials, the materials form a two phase mixture comprising a liquid phase and a solid phase. Other material systems may be partially soluble, such that two or more materials of the material system exhibit soluble behavior and over one or more limited ranges of compositions.

Additionally, in some embodiments, a coating material and a base alloy may be selected such that the coating material and base alloy form a eutectic material system in which a mixture of the coating material and the base alloy melts at a lower temperature than the melting temperatures of the coating material and the base alloy. In some such eutectic systems, the coating material and base alloy may form three distinct phases: a liquid (at high temperatures) in which the coating material and base alloy are miscible in one another, a first solid phase in which the coating material may exhibit limited solubility in the base alloy, and a second solid phase in which the base alloy may exhibit some solubility in the coating material. Each of the solid phases may be a solid solution exhibiting the crystal structure of the primary component. One exemplary material system that exhibits such eutectic behavior is the silver-copper material system (see FIG. 27B). In that material system, addition of silver to pure copper results in a mixture having a lower melting point compared to the melting point of pure copper. This reduction in the melting point continues with increased addition of silver until the mixture reaches the eutectic composition of approximately 39.9 atomic percent copper and 60.1 atomic percent silver; at the eutectic composition, the system exhibits its lowest possible melting temperature. Further addition of silver results in an increase in the melting temperature, up to the melting temperature of pure silver at 0 atomic percent copper. While the above-described example exhibits eutectic behavior over the entire composition range of the mixture, other systems in which eutectic behavior occurs over a limited range of composition also may be suitable. Moreover, while the above described eutectic material system includes two pure metal elements, other eutectic systems may be suitable, such as systems in which one or more component comprises a metal alloy, intermetallic compound, oxide, ceramic, or other suitable compound.

In some applications, the coating materials on the wires of the cable and the contact tails may be different and may provide different thermodynamic effects. For example, in one embodiment, the wires and contact tails may comprise similar or identical base alloys, but may have different coating materials. For instance, a first coating on the wires of the cable may be selected to form a eutectic alloy system (as described above) such that the addition of the first coating material to the base alloy effectively lowers the melting point of the base alloy of the wire; a second coating on the contact tails of the connector may be selected such that the coating material is partially or fully soluble with the base alloy of the connector such that the second coating material and the base alloy form a single phase solid or liquid over suitable composition ranges. As described in more detail below, such a configuration may allow for flow of material into an attachment interface and subsequent interdiffusion of the coating and base alloy materials to form a metallurgical bond along at least a portion of the attachment interface. While a particular configuration of first and second coatings is described above, it should be understood that other configurations may be suitable. For instance, in other embodiments, a first coating on the wires may be selected to be partially or fully soluble with the base alloy of the wire, and the second coating on the contact tails may be selected to form a eutectic system. In further embodiments, the first and second coatings may be selected to provide the same or similar type of thermodynamic response, such as forming a soluble mixture or a eutectic system.

Cable termination techniques as described herein may be used to terminate cables of any suitable type to conductive structures of any suitable type. Termination of a twinax cable to signal conductors of a connector is described as an example of a cable termination herein. Each signal conductor may include a contact tail, a mating contact portion, and an intermediate portion that extends between the contact tail and the mating contact portion. In some embodiments, the connector assembly may further include a plurality of cables. Each cable may include one or more wires. Each wire may be attached to a contact tail of a signal conductor of a connector using the above-described attachment and/or joining techniques.

In some embodiments, each of the pair of signal conductors of a connector may include broadsides and edges joining the broadsides. The pair of signal conductors may be formed by stamping a metal piece, with one or more tie bars connecting two opposing edges of the pair such that the separation between the pair is controlled by the size of the tie bar. The size of the tie bar may be selected based on the size of a wire in a cable to be attached, e.g., AWG 28, AWG 30, etc. The tie bar may set a spacing between opposing edges of the contact tails of the signal conductors such that, when the wire is attached to each edge, the separation between the wires yields a desired impedance, such as an impedance matching that of the cable or other parts of the interconnect.

Either before or after the wires are attached to the signal conductors, a housing may be molded around the pair of signal conductors such that the contact tails of the pair of signal conductors may be held in the housing in an edge-to-edge configuration. The tie bar then may be severed in order to isolate the pair of signal conductors. Compared with the conventional method of terminating cable wires on surfaces thus forming large bumps, attaching the cable wires to the edges allows for more precise control over the spacing between cable wires and reduces impedance mismatch. Impedance control may also be provided by an attachment that has a small impact on inductance at the conductor to wire interface, such as via the above-described attachment and/or joining techniques.

The foregoing principles are illustrated with an example, such as the interconnection system shown in FIG. 1. FIG. 1 illustrates an electrical interconnection system of the form that may be used in an electronic system. In this example, an orthogonal configuration, creates signal paths to a printed circuit board through a connector attached to an edge of a board. That connector is attached to the board at a footprint. Traces “breakout” of that footprint and are routed to other points on the board where they connect to other components. In this way, signals may be routed through a connector to a component anywhere on the board. However, in some scenarios, the board will be large enough that the distance between the connector and the component that receives a signal is long, such as greater than six inches. These long traces may undesirably degrade a signal carried on such a trace. FIG. 1 illustrates a configuration in which long traces are avoided, by facilitating integration of cables to carry signal over long distances.

FIG. 1 illustrates an electrical interconnection system 2800 including connectors 2802, 2804, 2900, cables 2806, and printed circuit boards (PCBs) 2801, 2803. Connector 2900 may include first type connector units 2902 and second type connector units 2904. The first type connector units may be directly mounted to PCB 2801. The second type connector units may be coupled to PCB 2801 through cables 2806. In the embodiment illustrated, cables 2806 connect to connector 2802, which in turn makes connections to PCB 2801.

In the illustrated example, connector 2900 includes both signal conductors configured to attach to a cable and to attach to a printed circuit board. Connector 2900 may be assembled from connector units that are configured for each type of attachment, such that there is a first type of connector units that have signal conductors configured to attach to a printed circuit board and a second type of connector units that have signal conductors configured to attach to a cable. However, the present invention is not limited in this regard. In some embodiments, cables may be terminated to other types of connectors or to conductors that are part of other types of electronic components.

Connector 2804 may be mounted to PCB 2803 at one end and mate with connector 2900 on the other end such that PCB 2803 is orthogonal to PCB 2801.

Cables 2806 may have first ends 2808 attached to the second type connector units 2904 and second ends 2810 attached to connector 2805. Connector 2805 is here mated to connector 2802, through which signals carried by the cables are coupled to PCB 2801. The second ends of the cables may be coupled to PCB 2801 at a location spaced from the first ends of the cables with a distance D. Any suitable value may be selected for the distance D. In some embodiments, D may be at least 6 inches, in the range of 1 to 20 inches, or any value within the range, such as between 6 and 20 inches. However, the upper limit of the range may depend on the size of PCB 2801, and the distance from connector 2900 that components (not shown) are mounted to PCB 2801, as connector 2802 may be mounted near components that receive or generate signals that pass through cables 2806. As a specific example, connector 2802 may be mounted within 6 inches of those components, and in some embodiments, will be mounted within 4 inches of those components or within 2 inches of those components.

Connector 2900 may be mated to any suitable type of connector. In some embodiments, mating connector 2804 may be an orthogonal connector. In the illustrated embodiments, both connectors 2900 and 2804 may have a modular construction, and similar modules may be used for corresponding components. Connector 2804 may be configured similarly to connector 600 illustrated in FIG. 2. In such an embodiment, connector 2900 may be configured as a direct attach orthogonal connector. That configuration may be achieved by attaching an extender, as described below, to a connector with a mating interface that is the same as the mating interface described in connection with connector 600.

As can be seen in FIG. 1, connector 600 includes contact tails 610 designed to attach to a PCB. These contact tails form one end of conductive elements that pass through the interconnection system. When the connectors are mounted to printed circuit boards, these contact tails will make electrical connection to conductive structures within the printed circuit board that carry signals or are connected to a reference potential. In the example illustrated the contact tails are press fit, “eye of the needle,” contacts that are designed to be pressed into vias in a printed circuit board. However, other forms of contact tails may be used.

Each of the connectors also has a mating interface where that connector can mate—or be separated from—the other connector. Connector 600 includes a mating interface 620. Though not fully visible in the view shown in FIG. 1, mating contact portions of the conductive elements are exposed at the mating interface.

Each of these conductive elements includes an intermediate portion that connects a contact tail to a mating contact portion. The intermediate portions may be held within a connector housing, at least a portion of which may be dielectric so as to provide electrical isolation between conductive elements. Additionally, the connector housings may include conductive or lossy portions, which in some embodiments may provide conductive or partially conductive paths between some of the conductive elements. In some embodiments, the conductive portions may provide shielding. The lossy portions may also provide shielding in some instances and/or may provide desirable electrical properties within the connectors.

In various embodiments, dielectric members may be molded or over-molded from a dielectric material such as plastic or nylon. Examples of suitable materials include, but are not limited to, liquid crystal polymer (LCP), polyphenyline sulfide (PPS), high temperature nylon or polyphenylenoxide (PPO) or polypropylene (PP). Other suitable materials may be employed, as aspects of the present disclosure are not limited in this regard.

All of the above-described materials are suitable for use as binder material in manufacturing connectors. In accordance some embodiments, one or more fillers may be included in some or all of the binder material. As a non-limiting example, thermoplastic PPS filled to 30% by volume with glass fiber may be used to form the entire connector housing or dielectric portions of the housings.

Alternatively or additionally, portions of the housings may be formed of conductive materials, such as machined metal or pressed metal powder. In some embodiments, portions of the housing may be formed of metal or other conductive material with dielectric members spacing signal conductors from the conductive portions. For example, a housing of a connector may have regions formed of a conductive material with insulative members separating the intermediate portions of signal conductors from the conductive portions of the housing.

The housing of connector 600 may also be formed in any suitable way. In the embodiment illustrated, daughtercard connector 600 may be formed from multiple units, which may be subassemblies, which may include one or more “wafers” and, in some embodiments, one or more extender modules, and one or more support members to hold the components together. Each of the wafers (700, FIG. 3) may include a housing portion, which may similarly include dielectric, lossy and/or conductive portions. One or more members may hold the wafers in a desired position. For example, support members 612 and 614 may hold top and rear portions, respectively, of multiple wafers in a side-by-side configuration. Support members 612 and 614 may be formed of any suitable material, such as a sheet of metal stamped with tabs, openings or other features that engage corresponding features on the individual wafers.

Other members that may form a portion of the connector housing may provide mechanical integrity for daughtercard connector 600 and/or hold the wafers in a desired position. For example, a front housing portion 640 (FIG. 2) may receive portions of the wafers forming the mating interface. Any or all of these portions of the connector housing may be dielectric, lossy and/or conductive, to achieve desired electrical properties for the interconnection system.

In some embodiments, each wafer may hold a column of conductive elements forming signal conductors. These signal conductors may be shaped and spaced to form single ended signal conductors. However, in the embodiment illustrated in FIG. 1, the signal conductors are shaped and spaced in pairs to provide differential signal conductors. Each of the columns may include or be bounded by conductive elements serving as ground conductors. It should be appreciated that ground conductors need not be connected to earth ground, but are shaped to carry reference potentials, which may include earth ground, DC voltages or other suitable reference potentials. The “ground” or “reference” conductors may have a shape different than the signal conductors, which are configured to provide suitable signal transmission properties for high frequency signals.

Conductive elements may be made of metal or any other material that is conductive and provides suitable mechanical properties for conductive elements in an electrical connector. Phosphor-bronze, beryllium copper and other copper alloys are non-limiting examples of materials that may be used. The conductive elements may be formed from such materials in any suitable way, including by stamping and/or forming.

The spacing between adjacent columns of conductors may be within a range that provides a desirable density and desirable signal integrity. As a non-limiting example, the conductors may be stamped from 0.4 mm thick copper alloy, and the conductors within each column may be spaced apart by 2.25 mm and the columns of conductors may be spaced apart by 2.4 mm. However, a higher density may be achieved by placing the conductors closer together. In other embodiments, for example, smaller dimensions may be used to provide higher density, such as a thickness between 0.2 and 0.4 mm or spacing of 0.7 to 1.85 mm between columns or between conductors within a column. Moreover, each column may include four pairs of signal conductors, such that a density of 60 or more pairs per linear inch is achieved for the interconnection system illustrated in FIG. 1. However, it should be appreciated that more pairs per column, tighter spacing between pairs within the column and/or smaller distances between columns may be used to achieve a higher density connector.

The wafers may be formed in any suitable way. In some embodiments, the wafers may be formed by stamping columns of conductive elements from a sheet of metal and over molding dielectric portions on the intermediate portions of the conductive elements. In other embodiments, wafers may be assembled from modules each of which includes a single, single-ended signal conductor, a single pair of differential signal conductors or any suitable number of single ended or differential pairs.

The inventors have recognized and appreciated that assembling wafers from modules may aid in reducing “skew” in signal pairs at higher frequencies, such as between about 25 GHz and 40 GHz, or higher. Skew, in this context, refers to the difference in electrical propagation time between signals of a pair that operates as a differential signal. Modular construction that reduces skew is designed described, for example in U.S. Pat. Nos. 9,509,101 and 9,450,344, which are incorporated herein by reference.

In accordance with techniques described in those patents incorporated by reference, in some embodiments, connectors may be formed of modules, each carrying a signal pair. The modules may be individually shielded, such as by attaching shield members to the modules and/or inserting the modules into an organizer or other structure that may provide electrical shielding between pairs and/or ground structures around the conductive elements carrying signals.

In some embodiments, signal conductor pairs within each module may be broadside coupled over substantial portions of their lengths. Broadside coupling enables the signal conductors in a pair to have the same physical length. To facilitate routing of signal traces within the connector footprint of a printed circuit board to which a connector is attached and/or constructing of mating interfaces of the connectors, the signal conductors may be aligned with edge to edge coupling in one or both of these regions. As a result, the signal conductors may include transition regions in which coupling changes from edge-to-edge to broadside or vice versa. As described below, these transition regions may be designed to prevent mode conversion or suppress undesired propagation modes that can interfere with signal integrity of the interconnection system.

The modules may be assembled into wafers or other connector structures. In some embodiments, a different module may be formed for each row position at which a pair is to be assembled into a right angle connector. These modules may be made to be used together to build up a connector with as many rows as desired. For example, a module of one shape may be formed for a pair to be positioned at the shortest rows of the connector, sometimes called the a-b rows. A separate module may be formed for conductive elements in the next longest rows, sometimes called the c-d rows. The inner portion of the module with the c-d rows may be designed to conform to the outer portion of the module with the a-b rows.

This pattern may be repeated for any number of pairs. Each module may be shaped to be used with modules that carry pairs for shorter and/or longer rows. To make a connector of any suitable size, a connector manufacturer may assemble into a wafer a number of modules to provide a desired number of pairs in the wafer. In this way, a connector manufacturer may introduce a connector family for a widely used connector size—such as 2 pairs. As customer requirements change, the connector manufacturer may procure tools for each additional pair, or, for modules that contain multiple pairs, group of pairs to produce connectors of larger sizes. The tooling used to produce modules for smaller connectors can be used to produce modules for the shorter rows even of the larger connectors. Such a modular connector is illustrated in FIG. 4.

Turning to FIG. 2, further details of connector 600 are shown in a partially exploded view. Components as illustrated in FIG. 2 may be assembled into a connector, configured to mate with backplane connector as described above. Alternatively or additionally, a subset of the connector components shown in FIG. 2 may be, in combination with other components, to form an orthogonal connector. Such an orthogonal connector may mate with a connector as shown in FIG. 2.

As shown, connector 600 includes multiple wafers 700A held together in a side-by-side configuration. Here, eight wafers, are shown. However, the size of the connector assembly may be configured by incorporating more rows per wafer, more wafers per connector or more connectors per interconnection system.

Conductive elements within the wafers 700A may include mating contact portions and contact tails. Contact tails 610 are shown extending from a surface of connector 600 adapted for mounting against a printed circuit board. In some embodiments, contact tails 610 may pass through a member 630. Member 630 may include insulative, lossy and/or conductive portions. In some embodiments, contact tails associated with signal conductors may pass through insulative portions of member 630. Contact tails associated with reference conductors may pass through lossy or conductive portions.

In some embodiments, the conductive or lossy portions may be compliant, such as may result from a conductive elastomer or other material that may be known in the art for forming a gasket. The compliant material may be thicker than the insulative portions of member 630. Such compliant material may be positioned to align with pads on a surface of a daughtercard to which connector 600 is to be attached. Those pads may be connected to reference structures within the printed circuit board such that, when connector 600 is attached to the printed circuit board, the compliant material makes contact with the reference pads on the surface of the printed circuit board.

The conductive or lossy portions of member 630 may be positioned to make electrical connection to reference conductors within connector 600. Such connections may be formed, for example, by contact tails of the reference conductors passing through the lossy of conductive portions. Alternatively or additionally, in embodiments in which the lossy or conductive portions are compliant, those portions may be positioned to press against the mating reference conductors when the connector is attached to a printed circuit board.

Mating contact portions of the wafers 700A are held in a front housing portion 640. The front housing portion may be made of any suitable material, which may be insulative, lossy and/or conductive or may include any suitable combination or such materials. For example the front housing portion may be molded from a filled, lossy material or may be formed from a conductive material, using materials and techniques similar to those described above for the housing walls 226. As shown, the wafers are assembled from modules 810A, 810B, 810C and 810D (FIG. 4), each with a pair of signal conductors surrounded by reference conductors. In the embodiment illustrated, front housing portion 640 has multiple passages, each positioned to receive one such pair of signal conductors and associated reference conductors. However, it should be appreciated that each module might contain a single signal conductor or more than two signal conductors.

Front housing 640, in the embodiment illustrated, is shaped to fit within walls of a connector. However, in some embodiments, as described in more detail below, the front housing may be configured to connect to an extender shell.

FIG. 3 illustrates a wafer 700. Multiple such wafers may be aligned side-by-side and held together with one or more support members, or in any other suitable way, to form a connector or, as described below, an orthogonal connector. In the embodiment illustrated, wafer 700 is a subassembly formed from multiple modules 810A, 810B, 810C and 810D. The modules are aligned to form a column of mating contact portions along one edge of wafer 700 and a column of contact tails along another edge of wafer 700. In the embodiment in which the wafer is designed for use in a right angle connector, as illustrated, those edges are perpendicular.

In the embodiment illustrated, each of the modules includes reference conductors that at least partially enclose the signal conductors. The reference conductors may similarly have mating contact portions and contact tails.

The modules may be held together in any suitable way. For example, the modules may be held within a housing, which in the embodiment illustrated is formed with members 900A and 900B. Members 900A and 900B may be formed separately and then secured together, capturing modules 810A . . . 810D between them. Members 900A and 900B may be held together in any suitable way, such as by attachment members that form an interference fit or a snap fit. Alternatively or additionally, adhesive, welding or other attachment techniques may be used.

Members 900A and 900B may be formed of any suitable material. That material may be an insulative material. Alternatively or additionally, that material may be or may include portions that are lossy or conductive. Members 900A and 900B may be formed, for example, by molding such materials into a desired shape. Alternatively, members 900A and 900B may be formed in place around modules 810A . . . 810D, such as via an insert molding operation. In such an embodiment, it is not necessary that members 900A and 900B be formed separately. Rather, a housing portion to hold modules 810A . . . 810D may be formed in one operation.

FIG. 4 shows modules 810A . . . 810D without members 900A and 900B. In this view, the reference conductors are visible. Signal conductors (not visible in FIG. 6) are enclosed within the reference conductors, forming a waveguide structure. Each waveguide structure includes a contact tail region 820, an intermediate region 830 and a mating contact region 840. Within the mating contact region 840 and the contact tail region 820, the signal conductors are positioned edge to edge. Within the intermediate region 830, the signal conductors are positioned for broadside coupling. Transition regions 822 and 842 are provided to transition between the edge coupled orientation and the broadside coupled orientation.

The transition regions 822 and 842 in the reference conductors may correspond to transition regions in signal conductors, as described below. In the illustrated embodiment, reference conductors form an enclosure around the signal conductors. A transition region in the reference conductors, in some embodiments, may keep the spacing between the signal conductors and reference conductors generally uniform over the length of the signal conductors. Thus, the enclosure formed by the reference conductors may have different widths in different regions.

The reference conductors provide shielding coverage along the length of the signal conductors. As shown, coverage is provided over substantially all of the length of the signal conductors, including coverage in the mating contact portion and the intermediate portions of the signal conductors. The contact tails are shown exposed so that they can make contact with the printed circuit board. However, in use, these mating contact portions will be adjacent ground structures within a printed circuit board such that being exposed as shown in FIG. 4 does not detract from shielding coverage along substantially all of the length of the signal conductor. In some embodiments, mating contact portions might also be exposed for mating to another connector. Accordingly, in some embodiments, shielding coverage may be provided over more than 80%, 85%, 90% or 95% of the intermediate portion of the signal conductors. Similarly, shielding coverage may also be provided in the transition regions, such that shielding coverage may be provided over more than 80%, 85%, 90% or 95% of the combined length of the intermediate portion and transition regions of the signal conductors. In some embodiments, as illustrated, the mating contact regions and some or all of the contact tails may also be shielded, such that shielding coverage may be, in various embodiments, over more than 80%, 85%, 90% or 95% of the length of the signal conductors.

In the embodiment illustrated, a waveguide-like structure formed by the reference conductors has a wider dimension in the column direction of the connector in the contact tail regions 820 and the mating contact region 840 to accommodate for the wider dimension of the signal conductors being side-by-side in the column direction in these regions. In the embodiment illustrated, contact tail regions 820 and the mating contact region 840 of the signal conductors are separated by a distance that aligns them with the mating contacts of a mating connector or contact structures on a printed circuit board to which the connector is to be attached.

These spacing requirements mean that the waveguide will be wider in the column dimension than it is in the transverse direction, providing an aspect ratio of the waveguide in these regions that may be at least 2:1, and in some embodiments may be on the order of at least 3:1. Conversely, in the intermediate region 830, the signal conductors are oriented with the wide dimension of the signal conductors overlaid in the column dimension, leading to an aspect ratio of the waveguide that may be less than 2:1, and in some embodiments may be less than 1.5:1 or on the order of 1:1.

With this smaller aspect ratio, the largest dimension of the waveguide in the intermediate region 830 will be smaller than the largest dimension of the waveguide in regions 830 and 840. Because the lowest frequency propagated by a waveguide is inversely proportional to the length of its shortest dimension, the lowest frequency mode of propagation that can be excited in intermediate region 830 is higher than can be excited in contact tail regions 820 and the mating contact region 840. The lowest frequency mode that can be excited in the transition regions will be intermediate between the two. Because the transition from edge coupled to broadside coupling has the potential to excite undesired modes in the waveguides, signal integrity may be improved if these modes are at higher frequencies than the intended operating range of the connector, or at least are as high as possible.

These regions may be configured to avoid mode conversion upon transition between coupling orientations, which would excite propagation of undesired signals through the waveguides. For example, as shown below, the signal conductors may be shaped such that the transition occurs in the intermediate region 830 or the transition regions 822 and 842, or partially within both. Additionally or alternatively, the modules may be structured to suppress undesired modes excited in the waveguide formed by the reference conductors, as described in greater detail below.

Though the reference conductors may substantially enclose each pair, it is not a requirement that the enclosure be without openings. Accordingly, in embodiments shaped to provide rectangular shielding, the reference conductors in the intermediate regions may be aligned with at least portions of all four sides of the signal conductors. The reference conductors may combine for example to provide 360 degree coverage around the pair of signal conductors. Such coverage may be provided, for example, by overlapping or physically contact reference conductors. In the illustrated embodiment, the reference conductors are U-shaped shells and come together to form an enclosure.

Three hundred sixty degree coverage may be provided regardless of the shape of the reference conductors. For example, such coverage may be provided with circular, elliptical or reference conductors of any other suitable shape. However, it is not a requirement that the coverage be complete. The coverage, for example, may have an angular extent in the range between about 270 and 365 degrees. In some embodiments, the coverage may be in the range of about 340 to 360 degrees. Such coverage may be achieved for example, by slots or other openings in the reference conductors.

In some embodiments, the shielding coverage may be different in different regions. In the transition regions, the shielding coverage may be greater than in the intermediate regions. In some embodiments, the shielding coverage may have an angular extent of greater than 355 degrees, or even in some embodiments 360 degrees, resulting from direct contact, or even overlap, in reference conductors in the transition regions even if less shielding coverage is provided in the transition regions.

The inventors have recognized and appreciated that, in some sense, fully enclosing a signal pair in reference conductors in the intermediate regions may create effects that undesirably impact signal integrity, particularly when used in connection with a transition between edge coupling and broadside coupling within a module. The reference conductors surrounding the signal pair may form a waveguide. Signals on the pair, and particularly within a transition region between edge coupling and broadside coupling, may cause energy from the differential mode of propagation between the edges to excite signals that can propagate within the waveguide. In accordance with some embodiments, one or more techniques to avoid exciting these undesired modes, or to suppress them if they are excited, may be used.

Some techniques that may be used increase the frequency that will excite the undesired modes. In the embodiment illustrated, the reference conductors may be shaped to leave openings 832. These openings may be in the narrower wall of the enclosure. However, in embodiments in which there is a wider wall, the openings may be in the wider wall. In the embodiment illustrated, openings 832 run parallel to the intermediate portions of the signal conductors and are between the signal conductors that form a pair. These slots lower the angular extent of the shielding, such that, adjacent the broadside coupled intermediate portions of the signal conductors, the angular extent of the shielding may be less than 360 degrees. It may, for example, be in the range of 355 of less. In embodiments in which members 900A and 900B are formed by over molding lossy material on the modules, lossy material may be allowed to fill openings 832, with or without extending into the inside of the waveguide, which may suppress propagation of undesired modes of signal propagation, that can decrease signal integrity.

In the embodiment illustrated in FIG. 4, openings 832 are slot shaped, effectively dividing the shielding in half in intermediate region 830. The lowest frequency that can be excited in a structure serving as a waveguide—as is the effect of the reference conductors that substantially surround the signal conductors as illustrated in FIG. 6—is inversely proportional to the dimensions of the sides. In some embodiments, the lowest frequency waveguide mode that can be excited is a TEM mode. Effectively shortening a side by incorporating slot-shaped opening 832, raises the frequency of the TEM mode that can be excited. A higher resonant frequency can mean that less energy within the operating frequency range of the connector is coupled into undesired propagation within the waveguide formed by the reference conductors, which improves signal integrity.

In region 830, the signal conductors of a pair are broadside coupled and the openings 832, with or without lossy material in them, may suppress TEM common modes of propagation. While not being bound by any particular theory of operation, the inventors theorize that openings 832, in combination with an edge coupled to broadside coupled transition, aids in providing a balanced connector suitable for high frequency operation.

FIG. 5 illustrates a member 900, which may be a representation of member 900A or 900B. As can be seen, member 900 is formed with channels 910A . . . 910D shaped to receive modules 810A . . . 810D shown in FIG. 6. With the modules in the channels, member 900A may be secured to member 900B. In the illustrated embodiment, attachment of members 900A and 900B may be achieved by posts, such as post 920, in one member, passing through a hole, such as hole 930, in the other member. The post may be welded or otherwise secured in the hole. However, any suitable attachment mechanism may be used.

Members 900A and 900B may be molded from or include a lossy material. Any suitable lossy material may be used for these and other structures that are “lossy.” Materials that conduct, but with some loss, or material which by another physical mechanism absorbs electromagnetic energy over the frequency range of interest are referred to herein generally as “lossy” materials. Electrically lossy materials can be formed from lossy dielectric and/or poorly conductive and/or lossy magnetic materials. Magnetically lossy material can be formed, for example, from materials traditionally regarded as ferromagnetic materials, such as those that have a magnetic loss tangent greater than approximately 0.05 in the frequency range of interest. The “magnetic loss tangent” is the ratio of the imaginary part to the real part of the complex electrical permeability of the material. Practical lossy magnetic materials or mixtures containing lossy magnetic materials may also exhibit useful amounts of dielectric loss or conductive loss effects over portions of the frequency range of interest. Electrically lossy material can be formed from material traditionally regarded as dielectric materials, such as those that have an electric loss tangent greater than approximately 0.05 in the frequency range of interest. The “electric loss tangent” is the ratio of the imaginary part to the real part of the complex electrical permittivity of the material. Electrically lossy materials can also be formed from materials that are generally thought of as conductors, but are either relatively poor conductors over the frequency range of interest, contain conductive particles or regions that are sufficiently dispersed that they do not provide high conductivity or otherwise are prepared with properties that lead to a relatively weak bulk conductivity compared to a good conductor such as copper over the frequency range of interest.

Electrically lossy materials typically have a bulk conductivity of about 1 siemen/meter to about 100,000 siemens/meter and preferably about 1 siemen/meter to about 10,000 siemens/meter. In some embodiments material with a bulk conductivity of between about 10 siemens/meter and about 200 siemens/meter may be used. As a specific example, material with a conductivity of about 50 siemens/meter may be used. However, it should be appreciated that the conductivity of the material may be selected empirically or through electrical simulation using known simulation tools to determine a suitable conductivity that provides both a suitably low crosstalk with a suitably low signal path attenuation or insertion loss.

Electrically lossy materials may be partially conductive materials, such as those that have a surface resistivity between 1 Ω/square and 100,000 Ω/square. In some embodiments, the electrically lossy material has a surface resistivity between 10 Ω/square and 1000 Ω/square. As a specific example, the material may have a surface resistivity of between about 20 Ω/square and 80 Ω/square.

In some embodiments, electrically lossy material is formed by adding to a binder a filler that contains conductive particles. In such an embodiment, a lossy member may be formed by molding or otherwise shaping the binder with filler into a desired form. Examples of conductive particles that may be used as a filler to form an electrically lossy material include carbon or graphite formed as fibers, flakes, nanoparticles, or other types of particles. Metal in the form of powder, flakes, fibers or other particles may also be used to provide suitable electrically lossy properties. Alternatively, combinations of fillers may be used. For example, metal plated carbon particles may be used. Silver and nickel are suitable metal plating for fibers. Coated particles may be used alone or in combination with other fillers, such as carbon flake. The binder or matrix may be any material that will set, cure, or can otherwise be used to position the filler material. In some embodiments, the binder may be a thermoplastic material traditionally used in the manufacture of electrical connectors to facilitate the molding of the electrically lossy material into the desired shapes and locations as part of the manufacture of the electrical connector. Examples of such materials include liquid crystal polymer (LCP) and nylon. However, many alternative forms of binder materials may be used. Curable materials, such as epoxies, may serve as a binder. Alternatively, materials such as thermosetting resins or adhesives may be used.

Also, while the above described binder materials may be used to create an electrically lossy material by forming a binder around conducting particle fillers, the application is not so limited. For example, conducting particles may be impregnated into a formed matrix material or may be coated onto a formed matrix material, such as by applying a conductive coating to a plastic component or a metal component. As used herein, the term “binder” encompasses a material that encapsulates the filler, is impregnated with the filler or otherwise serves as a substrate to hold the filler.

Preferably, the fillers will be present in a sufficient volume percentage to allow conducting paths to be created from particle to particle. For example, when metal fiber is used, the fiber may be present in about 3% to 40% by volume. The amount of filler may impact the conducting properties of the material.

Filled materials may be purchased commercially, such as materials sold under the trade name Celestran® by Celanese Corporation which can be filled with carbon fibers or stainless steel filaments. A lossy material, such as lossy conductive carbon filled adhesive preform, such as those sold by Techfilm of Billerica, Mass., US may also be used. This preform can include an epoxy binder filled with carbon fibers and/or other carbon particles. The binder surrounds carbon particles, which act as a reinforcement for the preform. Such a preform may be inserted in a connector wafer to form all or part of the housing. In some embodiments, the preform may adhere through the adhesive in the preform, which may be cured in a heat treating process. In some embodiments, the adhesive may take the form of a separate conductive or non-conductive adhesive layer. In some embodiments, the adhesive in the preform alternatively or additionally may be used to secure one or more conductive elements, such as foil strips, to the lossy material.

Various forms of reinforcing fiber, in woven or non-woven form, coated or non-coated may be used. Non-woven carbon fiber is one suitable material. Other suitable materials, such as custom blends as sold by RTP Company, can be employed, as the present invention is not limited in this respect.

In some embodiments, a lossy member may be manufactured by stamping a preform or sheet of lossy material. For example, an insert may be formed by stamping a preform as described above with an appropriate pattern of openings. However, other materials may be used instead of or in addition to such a preform. A sheet of ferromagnetic material, for example, may be used.

However, lossy members also may be formed in other ways. In some embodiments, a lossy member may be formed by interleaving layers of lossy and conductive material such as metal foil. These layers may be rigidly attached to one another, such as through the use of epoxy or other adhesive, or may be held together in any other suitable way. The layers may be of the desired shape before being secured to one another or may be stamped or otherwise shaped after they are held together.

FIG. 6 shows further details of construction of a wafer module 1000. Module 1000 may be representative of any of the modules in a connector, such as any of the modules 810A . . . 810D shown in FIGS. 3-4. Each of the modules 810A . . . 810D may have the same general construction, and some portions may be the same for all modules. For example, the contact tail regions 820 and mating contact regions 840 may be the same for all modules. Each module may include an intermediate portion region 830, but the length and shape of the intermediate portion region 830 may vary depending on the location of the module within the wafer.

In the embodiment illustrated, module 100 includes a pair of signal conductors 1310A and 1310B (FIG. 7) held within an insulative housing portion 1100. Insulative housing portion 1100 is enclosed, at least partially, by reference conductors 1010A and 1010B. This subassembly may be held together in any suitable way. For example, reference conductors 1010A and 1010B may have features that engage one another. Alternatively or additionally, reference conductors 1010A and 1010B may have features that engage insulative housing portion 1100. As yet another example, the reference conductors may be held in place once members 900A and 900B are secured together as shown in FIG. 3.

In the embodiments illustrated in FIG. 6, subregion 1042 includes projecting insulative members 1042A and 1042B, which can reduce the magnitude of changes in relative dielectric constant of material surrounding portions of a connector. Impedance control is also provided by projections 1020A and 1022A and 1020B and 1022B in the reference conductors 1010A and 1010B. These projections impact the separation, in a direction perpendicular to the axis of the signal conductor pair, between portions of the signal conductor pair and the reference conductors 1010A and 1010B. This separation, in combination with other characteristics, such as the width of the signal conductors in those portions, may control the impedance in those portions such that it approximates the nominal impedance of the connector or does not change abruptly in a way that may cause signal reflections. Other parameters of either or both mating modules may be configured for such impedance control.

Turning to FIG. 7, further details of exemplary components of a module 1000 are illustrated. FIG. 7 is an exploded view of module 1000, without reference conductors 1010A and 1010B shown. Insulative housing portion 1100 is, in the illustrated embodiment, made of multiple components. Central member 1110 may be molded from insulative material. Central member 1110 includes two grooves 1212A and 1212B into which conductive elements 1310A and 1310B, which in the illustrated embodiment form a pair of signal conductors, may be inserted.

Covers 1112 and 1114 may be attached to opposing sides of central member 1110. Covers 1112 and 1114 may aid in holding conductive elements 1310A and 1310B within grooves 1212A and 1212B and with a controlled separation from reference conductors 1010A and 1010B. In the embodiment illustrated, covers 1112 and 1114 may be formed of the same material as central member 1110. However, it is not a requirement that the materials be the same, and in some embodiments, different materials may be used, such as to provide different relative dielectric constants in different regions to provide a desired impedance of the signal conductors.

In the embodiment illustrated, grooves 1212A and 1212B are configured to hold a pair of signal conductors for edge coupling at the contact tails and mating contact portions. Over a substantial portion of the intermediate portions of the signal conductors, the pair is held for broadside coupling. To transition between edge coupling at the ends of the signal conductors to broadside coupling in the intermediate portions, a transition region may be included in the signal conductors. Grooves in central member 1110 may be shaped to provide the transition region in the signal conductors. Projections 1122, 1124, 1126 and 1128 on covers 1112 and 1114 may press the conductive elements against central portion 1110 in these transition regions.

In the embodiment illustrated in FIG. 7, it can be seen that the transition between broadside and edge coupling occurs over a region 1150. At one end of this region, the signal conductors are aligned edge-to-edge in the column direction in a plane parallel to the column direction. Traversing region 1150 in towards the intermediate portion, the signal conductors jog in opposition direction perpendicular to that plane and jog towards each other. As a result, at the end of region 1150, the signal conductors are in separate planes parallel to the column direction. The intermediate portions of the signal conductors are aligned in a direction perpendicular to those planes.

Region 1150 includes the transition region, such as 822 or 842 where the waveguide formed by the reference conductor transitions from its widest dimension to the narrower dimension of the intermediate portion, plus a portion of the narrower intermediate region 830. As a result, at least a portion of the waveguide formed by the reference conductors in this region 1150 has a widest dimension of W, the same as in the intermediate region 830. Having at least a portion of the physical transition in a narrower part of the waveguide reduces undesired coupling of energy into waveguide modes of propagation.

Having full 360 degree shielding of the signal conductors in region 1150 may also reduce coupling of energy into undesired waveguide modes of propagation. Accordingly, openings 832 do not extend into region 1150 in the embodiment illustrated.

In the embodiment illustrated, conductive members 1310A and 1310B each have edges and broader sides between those edges. Contact tails 1330A and 1330B are aligned in a column 1340. With this alignment, edges of conductive elements 1310A and 1310B face each other at the contact tails 1330A and 1330B. Other modules in the same wafer will similarly have contact tails aligned along column 1340. Contact tails from adjacent wafers will be aligned in parallel columns. The space between the parallel columns creates routing channels on the printed circuit board to which the connector is attached. Mating contact portions 1318A and 1318B are aligned along column 1344.

In the example of FIG. 7, conductive elements for a right angle connector are illustrated, as reflected by the right angle between column 1340, representing points of attachment to a daughtercard, and column 1344, representing locations for mating pins attached to a backplane connector.

FIG. 8 shows further detail of a module 1000. In this view, conductive elements 1310A and 1310B are shown separated from central member 1110. For clarity, covers 1112 and 1114 are not shown. Transition region 1312A between contact tail 1330A and intermediate portion 1314A is visible in this view. Similarly, transition region 1316A between intermediate portion 1314A and mating contact portion 1318A is also visible. Similar transition regions 1312 B and 1316B are visible for conductive element 1310B, allowing for edge coupling at contact tails 1330B and mating contact portions 1318B and broadside coupling at intermediate portion 1314B.

The mating contact portions 1318A and 1318B may be formed from the same sheet of metal as the conductive elements. However, it should be appreciated that, in some embodiments, conductive elements may be formed by attaching separate mating contact portions to other conductors to form the intermediate portions. For example, in some embodiments, intermediate portions may be cables such that the conductive elements are formed by terminating the cables with mating contact portions.

In the embodiment illustrated, the mating contact portions are tubular. Such a shape may be formed by stamping the conductive element from a sheet of metal and then forming to roll the mating contact portions into a tubular shape. The circumference of the tube may be large enough to accommodate a pin from a mating pin module, but may conform to the pin. The tube may be split into two or more segments, forming compliant beams. Two such beams are shown in FIG. 8. Bumps or other projections may be formed in distal portions of the beams, creating contact surfaces. Those contact surfaces may be coated with gold or other conductive, ductile material to enhance reliability of an electrical contact.

When conductive elements 1310A and 1310B are mounted in central member 1110, mating contact portions 1318A and 1318B fit within openings 1220A 1220B. The mating contact portions are separated by wall 1230. The distal ends 1320A and 1320B of mating contact portions 1318A and 1318B may be aligned with openings, such as opening 1222B, in platform 1232. Wall 1230, platform 1232 and insulative projecting members 1042A and 1042B may be formed as part of portion 1110, such as in one molding operation. However, any suitable technique may be used to form these members.

FIG. 8 shows a further technique that may be used, instead of or in addition to techniques described above, for reducing energy in undesired modes of propagation within the waveguides formed by the reference conductors in transition regions 1150. Conductive or lossy material may be integrated into each module so as to reduce excitation of undesired modes or to damp undesired modes. FIG. 8, for example, shows lossy region 1215. Lossy region 1215 may be configured to fall along the center line between signal conductors 1310A and 1310B in some or all of region 1150. Because signal conductors 1310A and 1310B jog in different directions through that region to implement the edge to broadside transition, lossy region 1215 may not be bounded by surfaces that are parallel or perpendicular to the walls of the waveguide formed by the reference conductors. Rather, it may be contoured to provide surfaces equidistant from the edges of the signal conductors 1310A and 1310B as they twist through region 1150. Lossy region 1215 may be electrically connected to the reference conductors in some embodiments. However, in other embodiments, the lossy region 1215 may be floating.

Though illustrated as a lossy region 1215, a similarly positioned conductive region may also reduce coupling of energy into undesired waveguide modes that reduce signal integrity. Such a conductive region, with surfaces that twist through region 1150, may be connected to the reference conductors in some embodiments. While not being bound by any particular theory of operation, a conductor, acting as a wall separating the signal conductors and as such twists to follow the twists of the signal conductors in the transition region, may couple ground current to the waveguide in such a way as to reduce undesired modes. For example, the current may be coupled to flow in a differential mode through the walls of the reference conductors parallel to the broadside coupled signal conductors, rather than excite common modes.

In some embodiments, an orthogonal connector may be constructed by attaching extender modules to a connector 600. The extender modules may be configured at both ends to mate with, or otherwise attach to, conductors as at mating interface 620. In this way, two connectors, both with a mating interface like mating interface 620, may mate. FIG. 9 illustrates one embodiment of an extender module 1500 that may be used in an orthogonal connector. The extender module includes a pair of signal conductors that have first mating contact portions 1510A and 1512A, and second mating contact portions 1510B and 1512B. The first and second mating contact portions are positioned at a first end 1502 and a second end 1504 of the extender module, respectively. As illustrated, the first mating contact portions are positioned along a first line 1550 that is orthogonal to a second line 1552 along which the second mating contact portions are positioned. In the depicted embodiment, the mating contact portions are shaped as pins and are configured to mate with a corresponding mating contact portion of a connector module 810; however, it should be understood that other mating interfaces, such as beams, blades, or any other suitable structure also may be used for the mating contact portions as the current disclosure is not so limited. As described in more detail below, conductive shield elements 1520A and 1520B are attached to opposing sides of the extender module 1500 in an intermediate portion 1510 between the first end 1502 and the second end 1504. The shield elements surround the intermediate portion such that the signal conductors within the extender module are fully shielded.

FIGS. 10A-10C illustrate further details of the signal conductors 1506 and 1508 disposed within the extender module 1500. Insulative portions of the extender module are also visible, as the shield elements 1520A and 1520B are not visible in these views. As shown in FIG. 10A, the first and second signal conductors are each formed as a single piece of conducting material with mating contact portions 1510 and 1512 connected by intermediate portions 1514 and 1516. The intermediate portions include a 90° bend such that the first mating portions are orthogonal to the second mating portions, as discussed above. Further, as illustrated, the bends in the first and second signal conductors are offset such that the lengths of the two signal conductors are substantially the same; such a construction may be advantageous to reduce and/or eliminate skew in a differential signal carried by the first and second signal conductors.

Referring now to FIGS. 10B and 10C, the intermediate portions 1514 and 1516 of signal conductors 1506 and 1508 are disposed within insulating material 1518. First and second portions of insulating material 1518A and 1518B are formed adjacent to the mating contact portions 1510 and 1512, and a third insulating portion 1522 is formed between the first and second portions around the intermediate portion of the signal conductors. Although in the depicted embodiment, the insulating material is formed as three separate portions, it should be understood that in other embodiments the insulating may be formed as a single portion, two portions, or as more than three portions, as the current disclosure is not so limited. The insulated portions 1518 and 1522 define orthogonal planar regions 1526 and 1528 on each side of the extender module to which the conductive elements 1520A and 1520B attach. Moreover, it is not a requirement that an extender module be formed using operations in the sequence illustrated in FIGS. 10A-10C. For example, the insulated portions 1518A and 1518B might be molded around signal conductors 1506 and 1508 prior to those conductive elements being bent at a right angle.

FIG. 11 shows an exploded view of an extender module 1500 and illustrates further details of the conductive shield elements 1520A and 1520B. The shield elements are shaped to conform to the insulating material 1518. As illustrated, the first shield element 1520A is configured to cover an outer surface of the extender module, and the second shield element 1520B is configured to cover an inner surface. In particular, the shield elements include first and second planar portions 1530A and 1530B shaped to attach to planar regions 1526 and 1528, respectively, and the planar portions are separated by a 90° bend 1532 such that the planar portions are orthogonal. The shield elements further include retention clips 1534A and 1534B, and tabs 1536, each of which attach to a corresponding feature on the insulating material 1518 or an opposing shield element to secure the shield elements to the extender module.

In the illustrated embodiment, the conductive shield elements 1520A and 1520B include mating contact portions formed as four compliant beams 1538A . . . 1538D. When assembled (FIG. 9), two of the compliant beams 1538A and 1538B are adjacent the first end 1502 of the extender module 1500; the other two compliant beams 1538C and 1538D are adjacent the second end 1504. Each pair of compliant beams is separated by an elongated notch 1540.

In some embodiments, the conductive shield elements 1520A and 1520B may have the same construction at each end, such that shield elements 1520A and 1520B may have the same shape, but a different orientation. However, in the embodiment illustrated shield elements 1520A and 1520B have a different construction at the first end 1502 and second end, respectively, such that shield elements 1520A and 1520B have different shapes. For example, as illustrated in FIG. 11, the compliant beams 1538C and 1538D adjacent the second end include fingers 1542 which are received in a corresponding pocket 1544. The fingers and pocket are constructed and arranged to introduce a pre-loading in the compliant beams which may aid in providing a reliable mating interface. For example, the pre-loading may cause the compliant beams to curve or bow outward from the extender module to promote mating contact as the second end of the extender module is received in a corresponding connector module.

Referring now to FIG. 12, two identical extender modules 1900A and 1900B are illustrated rotated 180° with respect to each other along a longitudinal axis of each module. As described in more detail below, the extender modules are shaped such that two modules may interlock when rotated in this manner to form a an extender module assembly 2000 (FIG. 13A). When interlocked in this manner, the first and second planar portions 1926A and 1928A on the first module are adjacent and parallel to the first and second planar portions 1926B and 1928B, respectively, on the second module.

FIG. 13A shows an extender module assembly including the two extender modules 1900A and 1900B of FIG. 12. As illustrated, the mating portions of the signal conductors 1910A . . . 1910D and 1912A . . . 1912D form two square arrays of mating contacts at the ends of the assembly. FIGS. 13B-13C illustrate schematic top and bottom views of the square arrays, respectively, and show the relative orientations of the mating portions of each signal conductor in the extender modules. In the depicted embodiment, the assembly has a center line 2002 parallel to a longitudinal axis of each extender module, and the center of each of the square arrays is aligned with the center line.

FIG. 14 illustrates one embodiment of an orthogonal connector 2100 during a stage of manufacture. Similar to connector 600, the orthogonal connector is assembled from connector modules and includes contact tails 2110 extending from a surface of the connector adapted for mounting to a printed circuit board. However, the connector 2100 further includes a front housing 2140 adapted to receive a plurality of extender modules. The front housing also includes retaining features 2150 to engage with corresponding features on an extender shell 2300, as described below. As shown, assemblies 2000 of extender modules may be simply slid into the front housing to facilitate simple assembly of a connector 2100.

FIG. 14 shows two, interlocked extender modules being inserter into the connector components. Inserting a pair of extender modules already interlocked avoids complexities of interlocking the extender modules after one is already inserted, but it should be appreciated that other techniques may be used to assemble the extender modules to the connector components. As an example of another variation, multiple pairs of extender modules may be inserted in one operation.

FIG. 15A depicts one embodiment of an extender shell 2300 for use with a direct attach orthogonal connector. The extender shell has a first side 2302 adapted to attach to the front housing 2140 of an orthogonal connector 2100. As shown, the first side includes cutouts 2350 in the outer wall 2306 adapted to engage with the retaining features 2150 on front housing 2140. As discussed below, the second side 2304 of the extender shell is configured for separable mating with a connector (e.g., a RAF connector). Further, the extender shell includes mounting holes 2310 which may be used to attach the extender shell to additional components of an interconnection system, such as a printed circuit board. A cross-sectional view of the extender shell is shown in FIG. 15B. Similar to the backplane connector 200, the extender shell includes lossy or conductive dividers 2320 and 2322 disposed in the first and second side of the extender shell, respectively.

Referring now to FIGS. 16A-16B, a direct attach connector 2400 includes an orthogonal connector 2100 having a front housing 2140 adapted to engage with an extender shell 2300. A plurality of extender modules are arranged as assemblies 2000 with shielded signal contacts positioned in square arrays, and the first ends of the extender modules are received in the front housing. As illustrated, the extender shell is placed over the extender modules and then secured to form connector 2400; the connector includes a mating end 2410 which may attach and mate with a connector such as connector 600 on an orthogonal printed circuit board, as discussed below.

FIG. 17 is a cross-sectional view of the assembled connector 2400. The mating ends of the extender modules 1500 are received in corresponding connector modules 810A . . . 810D on wafers 700. In the depicted embodiment, the extender modules are disposed within the extender shell. Further, the mating contact portions of the extender modules that are mated with the connector modules are orthogonal to the mating contact portions that extend into the mating end 2410 of the connector such that the connector may be used as a direct attach orthogonal connector.

FIG. 18 is a detailed view of the mating end 2410 of the connector 2400. The pins forming the mating contact portions of the extender modules are organized in an array of differential signal pairs, forming a mating interface. As discussed above, lossy or conductive dividers 2320 separate rows of signal pins.

FIG. 19 depicts one embodiment of an assembled orthogonal connector 2400 that may directly attach to a RAF connector such as connector 600 via a separable interface 2700. As shown, the contact tails 2210 of the connector 2400 are oriented orthogonally to the contact tails 610 of the connector 600. In this manner, printed circuit boards (not shown for simplicity) to which the connectors may be attached by their contact tails may be oriented orthogonally. It should be understood that although one orthogonal configuration for the connectors 2400 and 600 is depicted, in other embodiments, the connector may be rotated 180° to form a second orthogonal configuration. For example, the depicted configuration may correspond to a 90° rotation of connector 600 relative to connector 2400, and a second orthogonal configuration (not depicted) may correspond to a 270° rotation.

In the embodiment illustrated in FIG. 19, both connectors 2400 and connector 600 include conductive elements with contact tails configured to attach to a printed circuit board. In other embodiments, some or all of the modules used to form either or both of connectors may be replaced with modules having conductive elements configured to be terminated to conductors of a cable, as one way to create connectors with a configuration as illustrated in FIG. 1.

FIG. 20A-20B illustrate isometric views of connector 2900, looking from a mating interface 2920 and a mounting interface 2910 respectively. Connector 2900 may include an extender shell 2906 holding both the first type connector units 2902 and the second type connector unit 2904. The connector units may include signal conductors having mating contact portions 2912, contact tails 2914, and intermediate portions (not shown) that extend between the contact tails and the mating contact portions. The mating contact portions are shaped as pins in the illustrated embodiment. The pins are arranged to form pairs, with each pair extending parallel to direction 3006, and pairs aligned in column direction 3002, forming an array of pairs. The extender shell may include dividers 2908. The pairs of mating contact portions in each column may be separated by a divider.

In this example, the first type connector units 2902 include wafers 3008, which may be configured similar to a wafer 700 illustrated in FIG. 3. Rear portions of the wafers may be held by a support member 3014. In the illustrated embodiment, connector 2900 includes 10 wafers 3008. A wafer 3008 includes 6 wafer modules held by a housing made by two halves 3018A and 3018B. Each module includes a pair of differential signal conductors 2916A, 2916B.

As illustrated, for example in FIG. 14, the pairs of signal conductors within each of wafers 3008 may be aligned in column direction 3002. To achieve the orientation of pins at the mating interface illustrated in FIG. 21A, orthogonal extender modules, such as extender modules 2000 (FIG. 16) may be attached to the mating interfaces of the wafers 3008. FIGS. 21A-21E illustrate that connector 2900 may further include a plurality of extender modules 3010 attached to the mating ends of wafers 3008. The extender modules 3010 may be configured similar to the extender modules 1500 illustrated in FIGS. 9-11. Two identical extender modules 3010 may also form an extender module assembly 3012 similar to the extender module 2000 illustrated in FIGS. 13A-13B.

A plurality of wafers and a plurality of extender modules may be held by one or more support members 3004. In the embodiment illustrated, support members 3004 are implemented as at least two separate components 2902A and 2902B. However, any suitable number and shape of components may be used to form a support member. Additional components, for example, may hold the wafers at an opposing surface and/or at the sides of the structure shown. Alternatively or additionally, support member 3004 may be a housing, having an opening receiving and securing the wafers.

In the embodiment of FIG. 21A, member 2902A holds six wafers and member 2902B holds four wafers. The wafers held by 2902A are collectively attached to 24 extender modules 3010, and the wafers attached to member 2902B are collectively attached to 36 extender modules 3010. As each column of extender modules attaches to two wafers, those two wafers, and attached extender modules, may be regarded as a first type “unit,” and a connector may be formed with any suitable number of such units.

However, it should be appreciated that each first type connector unit may be a subassembly of any suitable number of components to implement any suitable number of columns of conductive elements or may be implemented as a single component or in any other suitable way. Using wafers and extender modules as illustrated, each first type connector unit may be formed from a multiple of two wafers, such as two, four, six or eight wafers and a multiple of that number of extender modules, the multiple being equal to the number of signal conductors in one wafer, but the application is not limited in this regard.

If multiple units are used, the connector units may be held together by a support member. In the embodiment illustrated, extender shell 2906 acts as a support member. The support member 3004 may include retaining features 2950 to engage with corresponding features 2960 on the extender shell 2906. It should be appreciated, however, that support members 3004 may, in some embodiments, may be omitted, if wafers are attached directly to extender shell 2906 or, if other supporting structures are used to hold the components of the connector together.

In FIGS. 21A-21E, the mating contact portions of the wafers 3008 are covered by the support members 3004 and not shown. However, the mating contact portions may be configured similar to the mating contact portions of wafers 700 illustrated in FIG. 3. Each wafer module of a wafer 3008 may include a pair of differential signal conductors. The mating contact portions of the wafer modules may be configured as receptacles adapted to receive the first mating contact portions of the extender modules, which may be configured as pins. The mating contact portions of the wafer modules in a wafer may be aligned in the direction of column 3002. Adjacent wafer modules, each from one of the two wafers 3008 in a first type connector unit 2902, may receive first mating contact portions of an extender module assembly 3012. As a result, second mating contact portions of the extender module assemblies may form an array 3202, in which pairs of differential signal conductors may be aligned in a direction of column 3006 perpendicular to the direction of column 3002.

In the illustrated example, there is one second type unit 2904. To be complementary with the first type units, the illustrative second type unit 2904 includes 12 cables 2806 aligned in a direction of column 3002. Each second type unit 2904 may include a plurality of modules 3100 held by a unit housing 3102. The plurality of modules in a second type unit may be aligned in the direction of column 3002. Each module 3100 may include a module housing 3112 holding a pair of signal conductors 3104A, 3104B. The pair of signal conductors are separated in the direction of column 3006. The mating contact portions of the second type units may form an array 3204. The arrays 3202 and 3204 together may form the mating interface 2920 of the connector 2900.

The mating contact portions of the signal conductors are illustrated as pins. However, other configurations may be adopted, e.g., receptacles. The contact tails (not shown) of the signal conductors are attached with cables 2806. The attachment interface between the contact tails and the cables are protected by at least the unit housing. Each cable may include a pair of wires, each of which is attached to a respective contact tail of a pair of signal conductors of a module. In some embodiments, the cables may be twin-ax cables. A shield surrounding the conductors of the twin-ax cable may be attached to a shield surrounding the conductive elements in a respective module 3100. The unit housing 3102 may extend farther in the direction of cable length than support members 3004 such that the attachment interface between the modules 3100 and the cables 2806 are covered.

FIGS. 22A-22B illustrate isometric views of a second type connector unit with cables attached to form a cable assembly 3400. A cable assembly 3400 may include an assembly housing 3402 holding a plurality of cable assembly modules 3420. Here, housing 3402 is made from two halves 3402A and 3402B that are secured together, capturing modules 3420 between them. These components may be held together through the use of adhesive, interference fit, heat staking or other suitable way.

The housing 3402 and the modules 3420 may form a second type connector unit. In the embodiment illustrated, each of the modules 3420 has a pair of signal conductors, and the modules 3420 are arranged such that the second type connector unit has two columns of signal conductors.

FIG. 22C illustrates an isometric view of a cable assembly module 3420, which may include a module 3408 of a second type connector unit 3404 and a cable 3406. The module 3408 may include a pair of signal conductors 3410A, 3410B held by a module housing 3412. Module 3408 may provide a mating interface matching the mating interface provided by each extender module used in forming the first type connector units.

Conductors of the cables such as wires may be attached to signal conductors within modules 3408 in any suitable way. However, in accordance with some embodiments, the cable conductors may be attached to edges of the signal conductors so as to provide a conducting structure of substantially uniform thickness and/or substantially uniform spacing between the conductive elements. For example, the thickness, including both the thickness of the conductor of the cable, the signal conductor and any weld, solder or other material to fuse the two may be no more than 10% greater than the thickness of the stock used to form the signal conductor. In some embodiments, the variation in thickness between the cable attachment and the stock thickness may be less than 25% or less than 50%. More generally, the variation in thickness may be less than the variation that might result from a conventional approach of attaching the cable conductor at the broadside to connector signal conductor, which might increase the thickness of the conducting path by 100% or more. Likewise, the separation at the attachment location may be relatively small, such as differing from the separation at the mating interface by no more than 10%.

Such a connection is illustrated in FIGS. 23A and 23B. FIG. 23A illustrates an isometric view of the pair of signal conductors 3410A, 3410B. Signal conductors 3410A, 3410B may represent signal conductors within a module 3408 or in any other cable connector. The signal conductors may include contact tails 3510, mating contact portions 3520, and intermediate portions 3530 that extend between the contact tails and the mating contact portions. The signal conductors may jog towards opposite directions in transition regions 3514, resulting a space s1 between the contact tails different from a space s2 between the intermediate portions and, in the embodiment illustrated, between the mating contact portions. In some embodiments, s1 may be larger than s2. The contact tails 3510 may include broadsides 3502 and edges 3504 joining the broadsides. The pair of signal conductors may be held with the contact tails in an edge-to-edge configuration, with an edge 3504A of signal conductor 3410A facing an edge 3504B of signal conductor 3410B. The mating contact portions 3520 may be configured as pins. In some embodiments, the pins may be made by rolling metal sheets.

FIG. 23B illustrates an isometric view of a cable 3406 attached to the pair of signal conductors 3410A, 3410B. The cable 3406 may include a pair of conductive elements 3510A, 3510B insulated by a dielectric portion 3512. Cable 3406 may additionally include a shield surrounding conductive elements 3510A, 3510B, which is not shown for simplicity. However, the shield may be attached to a shield or ground conductive in the cable connector.

Portions of the pair of conductive elements may be exposed out of the dielectric portion. The exposed portion of the conductive element 3510A may be attached to the edge 3504A of the signal conductor 3410A. The exposed portion of the conductive element 3510B may be attached to the edge 3504B of the signal conductor 3410B. The attachment may be made in any suitable way, such as by welding, soldering, or brazing. For example, laser welding may be used. For example, a laser welding operation may be performed in which a laser is aimed in a path along the edge of the conductive element, fusing the wire in the cable to the edge of the conductive element as the laser's point of focus changes.

In some embodiments, the laser may be controlled to form a running fillet joint between each conductive element of the cable and the edge of the signal conductor in the connector. The inventors have found that such a joint may be more reliable and more repeatable than a weld through a wire. A suitable weld may be formed with a commercially available green laser, but any suitable welding equipment may be used.

Operations such as welding, soldering, or brazing without any filler metal or other fusible material result in directly fusing the conductive elements of the cable to the conductive elements of the connector, thereby avoiding the bulk of conductive material that might be present if other attachment techniques, such as soldering using a filler metal, were used. Reducing the bulk of conductive material used for attachment may reduce changes in impedance, which can contribute to desirable electrical properties. However, in some embodiments, solder or other fusible material may be added to facilitate attachment.

Cable conductors may be attached to edges of conductive elements of any suitable shape in a connector. FIGS. 24A-24D illustrate a method of making a cable connector. FIG. 24A illustrates a plan view of a mounting interface 3640 between a structure 3630 and a cable 3606. FIG. 24B is an elevation view of the mounting interface 3640, illustrating the relatively small additional thickness at the attachment location. The structure 3630 may include a pair of signal conductors 3610A and 3610B joined by a tie bar 3602. The contact tails of the signal conductors may jog in opposite directions and away from the tie bar through transition regions 3614. The structure 3630 may be stamped from a sheet of metal, such that the dimensions of that structure may be accurately controlled by a stamping die.

The cable 3606 may include a pair of conductive elements 3620A, 3620B, each of which is attached to one of opposing edges of the signal conductors 3610A, 3610B. The pair of signal conductors 3610A and 3610B is spaced from each other by a distance d1 to accommodate the cable 3606. The distance d1 may be controlled by a width W of the tie bar 3602 and/or the degree of slopes in the transition regions 3614. This distance may be accurately controlled by the stamping.

FIG. 24C illustrates a plan view of a mounting interface 3642 between a structure 3630 and a cable 3606. FIG. 24C illustrates that an insulative housing 3650 has been molded over structure 3630. Housing 3650 may be molded using an insert molding operating or molded in any other suitable way. Tie bar 3602 has then been severed. In this configuration, conductive elements 3610A and 3610B have been separated. Spacing between conductive elements 3610A and 3610B is nonetheless maintained as both are embedded in housing 3650.

With tie bar 3602 severed, mating contacts 3604A and 3604B on conductive elements 3610A and 3610B may be formed to provide any suitable shape. Any suitable metal forming technique may be used. For example, the edges may be coined to provide mating contacts that are blades. Alternatively or additionally, the mating contacts may be rolled to provide mating contacts that are pins. As yet a further variation, the mating contacts may be shaped as single beam contacts, dual-beam contacts or multi-beam contacts. As a further alternative, separate components may be attached to conductive elements 3610A and 3610B, such as to form a multi-beam structure or to provide a receptacle.

The forming operations may leave mating contacts 3604A and 3604B spaced from each other by a distance d2, measured edge-to-edge. In the embodiment illustrated, d2 may approximate d1. For example, d2 may differ from d1 by 10% or less, or in some embodiments, 25% or 50% or less.

However, it is not a requirement that the separation between edges be uniform over the entire length of the contacts. The edges of the contacts at the attachment region may taper towards each other or may taper away from each other in a direction along the elongated axis of mating contacts 3604A and 3604B. Such a configuration may provide a gradual impedance transition from the cable the mating interface of the connector. Alternatively or additionally, the shape of the conductive elements 3610A and 3610B may vary over the length, such as to provide a wider or narrower width inside the housing relative to outside. As an example of a further variation, even if the opposing edges of conductive elements 3610A and 3610B are shaped to provide a uniform spacing d2 along the length of the conductive elements, the width of the conductive elements in the attachment may be controlled, even varying along the length of the conductive elements, by changing in the profile of the outer edges of conductive elements 3610A and 3610B. The outer edges, for example, may taper toward or away from each other.

The inventors have recognized and appreciated techniques for reliably joining a cable to an edge of a conductive element so as to provide cable terminations that yield interconnections with high signal integrity. Referring now to FIGS. 25A-25C, one embodiment of an attachment interface for joining a conductor of a cable (such as a wire) to an edge of a conductive element is described in more detail, using a contact tail of a signal conductor of a connector as an example. Similar to the embodiment described above in connection with FIG. 23B, FIG. 25A illustrates an isometric view of a cable 3706 attached to the pair of conductive elements, here shown as signal conductors 3410A, 3410B. The cable 3706 also may include a pair of conductive elements, here shown as conductors 3710A, 3710B (e.g., conductive wires) insulated by a dielectric portion 3712. Cable 3706 may additionally include a shield surrounding conductors 3710A, 3710B, which is not shown for simplicity. However, the shield may be attached to a shield or ground conductor in the cable connector. Portions of the pair of conductors may be exposed out of the dielectric portion. As described below, the exposed portion of the conductors 3710A may be attached to an edge of the signal conductor 3410A, and the exposed portion of the conductor 3710B may be attached to an edge of the signal conductor 3410B.

FIG. 25B shows a cross section taken along line B-B in FIG. 25A. In particular, FIG. 25B illustrates an attachment interface 3730 between the conductor 3710B (e.g., a wire) of the cable 3706 and the contact tail 3510 of the signal conductor 3410B of a connector. As illustrated, the generally round shape of the conductor 3710B results in a small contact area at the attachment interface 3730. The inventors have recognized and appreciated that this small contact area may lead to a poor quality joint, may lead to impedance discontinuities at the attachment interface, and/or may require the use of a relatively large amount of solder, braze, or other joining material to achieve a suitable joint; the inventors also have recognized that each of these may lead to undesirable signal degradation. Accordingly, in some embodiments, such as the embodiment illustrated in FIG. 25C, the conductor 3710B may be deformed prior to joining with the contact tail 3510 to provide a generally flattened contact area along the attachment interface 3730. Such a flattened contact area may provide a larger contact area between the conductor 3710B and the edge of the contact tail 3510, which may aid in maintaining a substantially constant impedance through the attachment interface and/or may facilitate joining the conductor to the contact tail with minimal or no additional joining material.

Additionally, as illustrated in FIG. 25B, in some embodiments, a diameter of the signal conductor 3710B (e.g., wire) of the cable 3706 may be larger than a thickness of the contact tail 3510 off the signal conductor 3410B of the connector. After deforming the signal conductor 3710B to form a flattened portion, the thickness of the flattened portion may be substantially equal to the thickness of the contact tail 3510, as illustrated in FIG. 25C. The inventors have recognized and appreciated that such flattening of the signal conductor 3710B may result in a joint structure that is more uniform in width and thickness compared to a joint formed without deforming the signal conductor 3710B, which may aid in maintaining a substantially constant impedance through the joint.

In some embodiments, a thickness of a flattened portion of signal conductor 3710B of the cable 3706 may be between about 75% and about 150% of a thickness of the contact tail 3510, and in some instances, the flattened portion of the signal conductor 3710B may have a thickness that is substantially equal to the thickness of the contact tail 3510. Additionally, in some embodiments, the thickness of the flattened portion of the signal conductor 3710B may be between about 50% and 100% of the diameter of the signal conductor within the cable 3706 (i.e., the diameter of the undeformed signal conductor 3710B). For instance, the thickness of the flattened portion may be between about 50% and 75% of the diameter of the signal conductor within the cable. The current disclosure is not limited to any particular method for flattening a conductor of a cable. For example, the conductor 3710B may be pressed against the edge of the contact tail 3510 during the joining process with a contact force sufficient to at least partially deform the conductor. In this manner, the conductor may be compressed between a tool (not depicted) and the edge of the contact tail to achieve a desired degree of deformation and flattening of the conductor, and thus, a desired contact area at the attachment interface. Such a tool may be implemented, for example, with a hardened member between conductors 2710A and 3710B. That portion may have a width, equal to a desired spacing between conductors 2710A and 3710B. Such a tool may also have members constraining motions of contact tails 3510. In operation, the tool might apply force on the ends of conductors 2710A and 2710B, in a direction parallel to the edges of contact tails 3510 so as to compress the conductors at the attachment interface 3730. Such compression may result in the ends of conductors 2710A and 2710B having a thickness approximating the thickness of the contact tails 3510. As displacement of the metal of conductors 2710A and 2710B is constrained on three sides by the tool, the metal of conductors 2710A and 2710B displaced by compression will move towards the contact tails 3510, creating flattened surfaces on the conductor facing the edges of contact tails 3510.

Alternatively or additionally, a separate tool may be used to partially or fully deform and flatten at least a portion of the conductor 3710B prior to joining with the contact tail 3510.

Shaping the conductors prior to attachment facilities a more robust attachment and provides for less changes in impedance. Further improvements may be achieved based on material selection and/or regulation of energy used to form the attachment. As discussed above, some aspects of the current disclosure relate to selecting materials for a conductor of a cable (e.g., a wire) and a contact tail of a signal conductor of a connector to facilitate joining, such as by providing desired material properties for the joining process. In some embodiments such thermodynamic properties may be achieved by coating one or both of the conductor and contact tail. For example, FIG. 26A depicts a cross sectional view of an attachment interface 3830 between a conductor 3812 of a cable and a contact tail 3810 of a connector, similar to the embodiment discussed above in connection with FIGS. 25A-25C. As illustrated, the contact tail 3810 comprises a first coating material 3816 at least partially surrounding a first base alloy 3814 of the contact tail. Similarly, the conductor 3812 comprises a second coating material 3820 at least partially surrounding a second base alloy 3818 of the conductor. While this embodiment utilizes first and second coating materials associated with the contact tail and conductor, it should be understood that the current disclosure is not limited to connectors having only two coating materials. For example, some embodiments may employ three or more coating materials on a contact tail and/or conductor.

In one embodiment, the first coating material 3816 and first base alloy 3814 may be selected such that the first coating material is soluble within the first base alloy (e.g., soluble over a substantial range of composition of the mixture of the first base alloy and first coating material) such that the first coating material and first base alloy may interdiffuse within each other to form a single phase solid solution. The second coating material 3820 and second base alloy 3818 may be selected such that the materials form a eutectic system. Specifically, a mixture of the second coating material and second base alloy may exhibit a lower melting temperature than either the melting temperature of the second base alloy or the second coating material. In some instances, the second coating material may exhibit some solid phase solubility in the and second base alloy (e.g., over a range of compositions of up to at least 1%, up to at least 5%, up to at least 10%, up to at least 20%, up to at least 30% or more of the second coating material in the second base alloy). In this manner, the dissolution of the second coating material in to the second base alloy may, in effect, lower the melting point of the second base alloy, as discussed above.

In some embodiments, the first and second base alloys may comprise one or more common primary component elements. For example, the first and second base alloys may both be copper alloys. However, other compositions and/or combinations of compositions also may be suitable, as would be apparent to one of skill in the art.

Referring now to FIG. 26B, attachment of the conductor 3812 to the contact tail 3810 is described in more detail. The attachment may be made using a suitable heat treating process, such as by heating a first side of the attachment interface 3830 via exposure to laser energy (e.g., a laser welding process). Compared to a typical laser welding or similar process in which the supplied energy must be sufficient to melt the materials along the entire attachment interface (thereby forming a heat effected zone that extends along the entire length of the joint, which can result in undesirable effects such as ablation and/or pitting), embodiments described herein may be joined with reduced power levels. For example, a relatively small heat effected zone 3832 may be formed at the end of the attachment interface 3830 to which the heat is applied, and a metallurgical bond 3834 may be formed along the remainder of the attachment interface. In particular, the heat applied during the heat treatment process may be sufficient to reach the reduced melting point of the mixture of the second base alloy 3818 and second coating material 3820 such that the mixture can flow into the attachment interface 3830 (e.g., due to gravitational and/or capillary forces). Depending on the particular embodiment, the heat effected zone 3832 may extend along less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, or less than 5% of the attachment interface 3830. Similarly, the metallurgical bond 3834 may extend along more than 50%, more than 60%, more than 70%, more than 80%, more than 90%, or more than 95% of the attachment interface 3830.

In some embodiments, the metallurgical bond 3834 may extend along a substantial portion of a length of the attachment interface 3830 along a direction parallel to the length of the conductor 3812. For example, the metallurgical bond may extend along at least 50%, at least 75%, at least 90% or more of the length of the attachment interface. In some exemplary embodiments, the length of the attachment interface may be between about 0.005 inches and about 0.02 inches (e.g., between about 0.01 inches and about 0.015 inches), and the metallurgical bond may extend along a length of at least 0.0025 inches, at least 0.005 inches, at least 0.01 inches, at least 0.015 inches, at least 0.018 inches or more of the attachment interface.

Moreover, elevated temperatures at an attachment interface during the heat treatment process described above may result in faster diffusion of the various materials. Consequently, a metallurgical bond 3834 may be formed along the attachment interface 3830 via the interdiffusion of the first base alloy 3814, first coating material 3816, second base alloy 3818, and second coating material 3820. In particular, the metallurgical bond 3834 may form a region along the attachment interface in which the first and second base alloys and first and second coating materials form a substantially homogeneous microstructure without a well-defined interface between the conductor 3812 and contact tail 3810.

Although the metallurgical bond 3834 is depicted as extending substantially along the entire thickness of the attachment interface below the heat effected zone 3832, it should be understood that other configurations may be suitable. For example, in some embodiments a suitable bond may be formed with a metallurgical bond along only a portion of the thickness of the attachment interface. Alternatively or additionally, in some embodiments, the attachment interface may be heated from both sides such that heat effected zones may be formed at both sides ends of the attachment interface (along the thickness of the attachment interface) and metallurgical bonds may extend from each heat effected zone, or may span the attachment interface between the heat effected zones. In some embodiments, the heat effected zone(s) may comprise a region in which the applied heat is sufficient to melt at least a portion of the base alloys and form a liquid mixture, which may subsequently solidify into one or more distinct phases. In such embodiments, the heat effected zone(s) may be characterized as welded portions of an attachment interface. Alternatively or additionally, the heat affected zone(s) may comprise regions in which the applied heat was sufficient to create a change in microstructure relative to the microstructure of the base alloy(s) and/or coating(s). Moreover, in some embodiments, a ratio of the thickness of the metallurgical bond in a direction along the thickness of the contact tail to the total thickness of the heat affected zone(s) may be at least 2:1, at least 3:1, at least 4:1, at least 5:1, or more.

In one exemplary embodiment, the contact tail may comprise a precipitation hardened copper alloy as the first base alloy, and the first coating material may be nickel. As shown in the phase diagram illustrated in FIG. 27A, nickel and copper would be regarded as completely soluble in each other at room temperature. As a result, copper from the first base alloy may diffuse into the nickel coating such that some copper is present near the surface of the first coating material (and similarly, some of the nickel coating may diffuse into the copper base alloy of the contact tail). The conductor of the cable may comprise electrolytic tough pitch (ETP) copper as the second base alloy, and the second coating material on the conductor may be silver. As shown in the phase diagrams illustrated in FIGS. 27B and 27C, silver and copper form a eutectic system with some limited solubility of silver into copper, while silver and nickel would be regarded as completely insoluble with one another. As a result, it is typically difficult to join silver coated parts to nickel coated parts. However, using the techniques described herein, upon heating the attachment interface between the conductor and the contact tail, a silver-copper mixture may melt and flow into to the attachment interface, and some of the copper may diffuse into the copper-nickel solid solution of the contact tail. Similarly, for example, some of the copper from the contact tail may diffuse into the copper silver mixture. In this manner, the interdiffusion of the copper, nickel, and silver at the attachment interface may lead to the formation of a metallurgical bond along at least a portion of the attachment interface.

Having thus described several embodiments, it is to be appreciated various alterations, modifications, and improvements may readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be within the spirit and scope of the application. Accordingly, the foregoing description and drawings are by way of example only. Various changes may be made to the illustrative structures, materials and processes shown and described herein.

For example, while certain combinations of alloys and/or materials were described above in connection with one illustrative embodiment, it should be understood that other compositions may be suitable. Moreover, the current disclosure is not limited to configurations in which the first and second base alloys are different types of alloys and/or the first and second coating materials comprise different materials. For example, in one embodiment, a silver coating could be employed on both the conductor and the contact tail. Accordingly, it should be understood that the current disclosure is not limited to metallurgical bonds formed from a soluble material system (e.g., Ni—Cu) and a eutectic or eutectoid system (e.g., Ag—Cu), and that one or both of these material systems may be used in connection with either of the conductor of the cable and the contact tail of the connector. Moreover, the various alloys or metals used for the base alloys and/or coatings may be selected for any of a variety of purposes, including, but not limited to, providing a desired electrical conductivity, corrosion resistance, and/or melting point reduction. For instance, in certain embodiments, tin may be incorporated into one or more coating materials (such as a silver or nickel coating) to further reduce the melting point of the mixture. In another embodiment, a silver-plated copper wire may be joined to a bare copper contact tail.

Additionally, while embodiments have been described in connection with joining a conductor (such as a wire) of a cable to a contact tail of a connector, it should be understood that the techniques described herein may be suitable for forming other types of joints, such as between contact tails on signal conductors of different connectors.

As another example, a method of manufacturing a module for a cable connector was described in connection with FIGS. 24A-24D. Steps of the method may be performed in an order other than as described. Cable conductors may be attached after a housing a formed and/or after a time bar is severed. Moreover, additional examples of methods for attaching a cable to a connector were described in connection with FIGS. 25A-26B. Steps of these methods may be combined in any suitable manor, including with the steps described above in connection with FIGS. 24A-24D. For example, the joining techniques described in connection with FIGS. 25A-26B may be combined with the techniques utilizing a tie bar described in connection with FIGS. 24A-24D.

As another example, techniques are described for improving signal quality at the mating interface of an electrical interconnection system. These techniques may be used alone or in any suitable combination. Furthermore, the size of a connector may be increased or decreased from what is shown. Also, it is possible that materials other than those expressly mentioned may be used to construct the connector. As another example, connectors with four differential signal pairs in a column are used for illustrative purposes only. Any desired number of signal conductors may be used in a connector.

As another example, an embodiment was described in which a different front housing portion is used to hold connector modules in a connector configuration versus an orthogonal configuration. It should be appreciated that, in some embodiments, a front housing portion may be configured to support either use.

Manufacturing techniques may also be varied. For example, embodiments are described in which the connector 600 is formed by organizing a plurality of wafers onto a stiffener. It may be possible that an equivalent structure may be formed by inserting a plurality of shield pieces and signal receptacles into a molded housing.

As another example, connectors are described that are formed of modules, each of which contains one pair of signal conductors. It is not necessary that each module contain exactly one pair or that the number of signal pairs be the same in all modules in a connector. For example, a 2-pair or 3-pair module may be formed. Moreover, in some embodiments, a core module may be formed that has two, three, four, five, six, or some greater number of rows in a single-ended or differential pair configuration. Each connector, or each wafer in embodiments in which the connector is waferized, may include such a core module. To make a connector with more rows than are included in the base module, additional modules (e.g., each with a smaller number of pairs such as a single pair per module) may be coupled to the core module.

As a further variation, FIGS. 21A-21E illustrate a connector in which columns of signal conductors are formed by wafers that have only signal conductor with contact tails for mounting to a printed circuit board or signal conductors with tails terminated to cables. It is not a requirement that all of the signal conductors within each wafer have the same configuration. A wafer, for example, may have some signal conductors configured to mount to a printed circuit board and others configured to terminate a cable. Further, it is not a requirement that the connector be assembled from wafers at all. In some embodiments, modules, each containing one, a pair or more of signal conductors may be held together as a connector.

Furthermore, although many inventive aspects are shown and described with reference to a orthogonal connector having a right angle configuration, it should be appreciated that aspects of the present disclosure is not limited in this regard, as any of the inventive concepts, whether alone or in combination with one or more other inventive concepts, may be used in other types of electrical connectors, such as backplane connectors, daughterboard connectors, midplane connectors, cable connectors, stacking connectors, mezzanine connectors, I/O connectors, chip sockets, etc.

In some embodiments, contact tails were illustrated as press fit “eye of the needle” compliant sections that are designed to fit within vias of printed circuit boards. However, other configurations may also be used, such as surface mount elements, spring contacts, solderable pins, etc., as aspects of the present disclosure are not limited to the use of any particular mechanism for attaching connectors to printed circuit boards.

Further, signal and ground conductors are illustrated as having specific shapes. In the embodiments above, the signal conductors were routed in pairs, with each conductive element of the pair having approximately the same shape so as to provide a balanced signal path. The signal conductors of the pair are positioned closer to each other than to other conductive structures. One of skill in the art will understand that other shapes may be used, and that a signal conductor or a ground conductor may be recognized by its shape or measurable characteristics. A signal conductor in many embodiments may be narrow relative to other conductive elements that may serve as reference conductors to provide low inductance. Alternatively or additionally, the signal conductor may have a shape and position relative to a broader conductive element that can serve as a reference to provide a characteristic impedance suitable for use in an electronic system, such as in the range of 50-120 Ohms. Alternatively or additionally, in some embodiments, the signal conductors may be recognized based on the relative positioning of conductive structures that serve as shielding. The signal conductors, for example, may be substantially surrounded by conductive structures that can serve as shield members.

Further, the configuration of connector modules and extender modules as described above provides shielding of signal paths through the interconnection system formed by connector modules and extender modules in a first connector and connector modules in a second connector. In some embodiments, minor gaps in shield members or spacing between shield members may be present without materially impacting the effectiveness of this shielding. It may be impractical, for example, in some embodiments, to extend shielding to the surface of a printed circuit board such that there is a gap on the order of 1 mm. Despite such separation or gaps, these configurations may nonetheless be regarded as fully shielded.

Moreover, examples of an extender module are pictured with an orthogonal configuration. It should be appreciated that, without a 90 degree twist, the extender modules may be used to form a RAM, if the extender module has pins or blades at its second end. Other types of connectors may alternatively be formed with modules with receptacles or mating contacts of other configurations at the second end.

Moreover, the extender modules are illustrated as forming a separable interface with connector modules. Such an interface may include gold plating or plating with some other metal or other material that may prevent oxide formation. Such a configuration, for example, may enable modules identical to those used in a connector to be used with the extender modules. However, it is not a requirement that the interface between the connector modules and the extender modules be separable. In some embodiments, for example, mating contacts of either the connector module or extender module may generate sufficient force to scrape oxide from the mating contact and form a hermetic seal when mated. In such an embodiment, gold and other platings might be omitted.

Connectors configured as described herein may provide desirable signal integrity properties across a frequency range of interest. The frequency range of interest may depend on the operating parameters of the system in which such a connector is used, but may generally have an upper limit between about 15 GHz and 50 GHz, such as 25 GHz, 30 or 40 GHz, although higher frequencies or lower frequencies may be of interest in some applications. Some connector designs may have frequency ranges of interest that span only a portion of this range, such as 1 to 10 GHz or 3 to 15 GHz or 5 to 35 GHz.

The operating frequency range for an interconnection system may be determined based on the range of frequencies that can pass through the interconnection with acceptable signal integrity. Signal integrity may be measured in terms of a number of criteria that depend on the application for which an interconnection system is designed. Some of these criteria may relate to the propagation of the signal along a single-ended signal path, a differential signal path, a hollow waveguide, or any other type of signal path. Two examples of such criteria are the attenuation of a signal along a signal path or the reflection of a signal from a signal path.

Other criteria may relate to interaction of multiple distinct signal paths. Such criteria may include, for example, near end cross talk, defined as the portion of a signal injected on one signal path at one end of the interconnection system that is measurable at any other signal path on the same end of the interconnection system. Another such criterion may be far end cross talk, defined as the portion of a signal injected on one signal path at one end of the interconnection system that is measurable at any other signal path on the other end of the interconnection system.

As specific examples, it could be required that signal path attenuation be no more than 3 dB power loss, reflected power ratio be no greater than −20 dB, and individual signal path to signal path crosstalk contributions be no greater than −50 dB. Because these characteristics are frequency dependent, the operating range of an interconnection system is defined as the range of frequencies over which the specified criteria are met.

Designs of an electrical connector are described herein that may provide desirable signal integrity for high frequency signals, such as at frequencies in the GHz range, including up to about 25 GHz or up to about 40 GHz or higher, while maintaining high density, such as with a spacing between adjacent mating contacts on the order of 3 mm or less, including center-to-center spacing between adjacent contacts in a column of between 1 mm and 2.5 mm or between 2 mm and 2.5 mm, for example. Spacing between columns of mating contact portions may be similar, although there is no requirement that the spacing between all mating contacts in a connector be the same.

Examples of arrangements that may be implemented according to some embodiments include the following:

1. A connector assembly, comprising:

a first signal conductor having a first contact tail, the first contact tail including an edge having a first planar surface; and

a first wire extending from a cable, wherein a portion of the first wire is at least partially flattened to form a second planar surface, and wherein the first wire is attached to the edge of the first contact tail with the second planar surface of the first wire in contact with the first planar surface of the first contact tail.

2. The connector assembly of arrangement 1, further comprising:

a second signal conductor having a second contact tail, the second contact tail including an edge having a third planar surface; and

a second wire extending from the cable, wherein a portion of the second wire is at least partially flattened to form a fourth planar surface, and wherein the second wire is attached to the edge of the second contact tail with the fourth planar surface of the second wire in contact with the third planar surface of the second contact tail.

3. The connector assembly of arrangement 2, wherein the edge of the first contact tail and the edge of the second contact tail are opposing edges in a pair of signal conductors.

4. The connector assembly of arrangement 3, wherein the pair of signal conductors are configured as a differential pair.

5. The connector assembly of any of arrangement 3-4, wherein:

the pair of signal conductors is a first pair of a plurality of pairs of signal conductors;

each of the plurality of pairs of signal conductors has a pair of contact tails with opposing edges;

the connector assembly comprises wires at least partially flattened to form planar surfaces attached to respective edges of each pair of contact tails of the plurality of pairs of signal conductors with the planar surfaces in contact with the opposing edges of the respective contact tails;

the pairs of signal conductors are separated by shielding.

6. The connector assembly of arrangement 5, wherein:

the plurality of pairs of signal conductors are disposed in a line.

7. The connector assembly of any of arrangement 5-6, wherein:

the plurality of pairs of signal conductors are disposed in a plurality of parallel lines.

8. The connector assembly of any of arrangement 5-7, wherein:

the wires attached to respective edges of each pair of contact tails comprise conductors of a twinax cable.

9. The connector assembly of any of arrangement 5-8, wherein:

the wires attached to respective edges of each pair of contact tails are via metallurgical bonds.

10. The connector assembly of any of arrangement 2-9, wherein the first and third planar surfaces face one another.

11. The connector assembly of any of arrangement 1-10, wherein the first wire is joined to the first signal conductor via a metallurgical bond extending at least partially along an interface between the first planar surface and the second planar surface.

12. The connector assembly of arrangement 11, wherein a length of the interface along a direction parallel to a direction of extension of the wire is between about 0.005 inches and about 0.02 inches.

13. The connector assembly of arrangement 12, wherein the length of the interface is between about 0.01 inches and about 0.015 inches.

14. The connector assembly of any of arrangement 12-13, wherein the metallurgical bond extends along at least 50% of the interface.

15. The connector assembly of arrangement 14, wherein the metallurgical bond extends along at least 75% of the interface.

16. The connector assembly of arrangement 15, wherein the metallurgical bond extends along at least 90% of the interface.

17. The connector assembly of any of arrangement 1-16, wherein a thickness of the portion of the wire is between about 75% and about 150% of a thickness of the first contact tail.

18. The connector assembly of arrangement 17, wherein the thickness of the portion of the wire is substantially equal to the thickness of the first contact tail.

19. The connector assembly of any of arrangements 1-18, wherein a thickness of the portion of the wire is greater than about 50% of a diameter of the wire within the cable.

20. The connector assembly of arrangement 19, wherein the thickness of the portion of the wire is less than 75% of the diameter of the wire within the cable.

21. The connector assembly of any of arrangements 1-20, wherein:

the first wire is attached to the edge of the first contact tail via a bond; and at least a portion of the bond is a metallurgical bond.

22. A connector assembly, comprising:

a signal conductor having a contact tail, the contact tail comprising an edge; and

a wire extending from a cable and attached to the edge of the contact tail via a bond extending along an attachment interface, wherein at least a portion of the bond is a metallurgical bond.

23. The connector of arrangement 22, wherein the metallurgical bond extends along at least 50 percent of the attachment interface.

24. The connector of any of arrangements 22-23, wherein the bond comprises a heat effected zone at a first end of the attachment interface.

25. The connector of any of arrangements 22-24, wherein the bond extends along the entire attachment interface.

26. The connector of any of arrangements 22-25, wherein the signal conductor comprises a first base alloy and a first coating material, and wherein the wire comprises a second base alloy and a second coating material.

27. The connector of arrangement 26, wherein the metallurgical bond comprises, at least in part, a region in which the first base alloy, first coating material, second base alloy, and second coating material are interdiffused with one another.

28. The connector of any of arrangements 26-27, wherein the first coating material is soluble in the first base alloy, and the second coating material and second base alloy form a eutectic material system.

29. The connector of any of arrangements 26-28, wherein the first and second base alloys comprise copper.

30. The connector of arrangement 29, wherein the first coating material comprises nickel and the second coating material comprises silver.

31. The connector of arrangement 30, wherein the second coating material further comprises tin.

32. The connector of any of arrangements 22-31, wherein at least a portion of the wire extending along the attachment interface is deformed such that a thickness of the portion is less than a diameter of the wire in the cable.

33. A method of forming an electrical connector, the method comprising:

bonding a wire of a cable to an edge of contact tail of a signal conductor along an attachment interface, at least in part, by interdiffusing at least a portion of a first material and a second material across the attachment interface to form a metallurgical bond.

34. The method of arrangement 33, wherein bonding the wire of the cable to the edge of the contact tail further comprises at least partially melting the first material and flowing the first material into the attachment interface.

35. The method of any of arrangements 33-34, wherein the first material comprises a first base alloy of the wire and a first coating material on the wire.

36. The method of arrangement 35, wherein the first base alloy and first coating material form a eutectic material system.

37. The method of any of arrangements 33-36, further comprising deforming at least a portion of the wire before bonding the wire to the contact tail.

38. The method of arrangement 37, wherein deforming at least a portion of the wire comprises flattening the portion of the wire.

39. The method of any of arrangements 33-38, wherein melting the first material comprises increasing the temperature of the first material to a temperature between about 800° C. and about 1100° C.

40. The method of any of arrangements 33-29, wherein the metallurgical bond extends along at least 50% of a length of the attachment interface.

41. The method of arrangement 40, wherein the metallurgical bond extends along at least 75% of a length of the attachment interface.

42. The method of arrangement 41, wherein the metallurgical bond extends along at least 90% of a length of the attachment interface.

43. A method of forming an electrical connector, the method comprising:

deforming a portion of a first wire of a cable to form a first planar surface; and

attaching the first wire to an edge of a first contact tail of a first signal conductor, at least in part, by contacting the first planar surface of the first wire to a second planar surface of the edge of the first contact tail.

44. The method of arrangement 43, further comprising:

deforming a portion of a second wire of the cable to form a third planar surface; and

attaching the second wire to an edge of a second contact tail of a second signal conductor, at least in part, by contacting the third planar surface of the second wire to a fourth planar surface of the edge of the second contact tail.

45. The method of arrangement 44, wherein the edge of the first contact tail and the edge of the second contact tail are opposing edges in a pair of signal conductors.

46. The method of arrangement 45, wherein the pair of signal conductors are configured as a differential pair.

47. The method of any of arrangements 45-46, further comprising attaching the wires to respective edges of the pair of contact tails via metallurgical bonds.

48. The method of any of arrangements 43-47, wherein deforming the portion of the first wire comprises flattening the portion of the first wire.

49. The method of arrangement 48, wherein after flattening, a thickness of the portion of the first wire is greater than about 50% of a diameter of the first wire within the cable.

50. The method of arrangement 49, wherein after flattening, the thickness of the portion of the first wire is less than about 75% of the diameter of the first wire within the cable.

51. The method of any of arrangements 48-50, wherein after flattening, a thickness of the portion of the first wire is between about 75% and about 150% of a thickness of the first contact tail.

52. The method of any of arrangements 43-51, wherein attaching the first wire to the edge of the first contact tail comprises forming a bond along the attachment interface, and wherein at least a portion of the bond is a metallurgical bond.

Accordingly, the present disclosure is not limited to the details of construction or the arrangements of components set forth in the following description and/or the drawings. Various embodiments are provided solely for purposes of illustration, and the concepts described herein are capable of being practiced or carried out in other ways. Also, the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” “having,” “containing,” or “involving,” and variations thereof herein, is meant to encompass the items listed thereafter (or equivalents thereof) and/or as additional items. 

What is claimed is:
 1. A connector assembly, comprising: a signal conductor having a contact tail, the contact tail comprising an edge; and a wire extending from a cable and attached to the edge of the contact tail via a bond extending along an attachment interface, wherein at least a portion of the bond is a metallurgical bond.
 2. The connector of claim 1, wherein the metallurgical bond extends along at least 50 percent of the attachment interface.
 3. The connector of claim 1, wherein the bond comprises a heat effected zone at a first end of the attachment interface.
 4. The connector of claim 1, wherein the signal conductor comprises a first base alloy and a first coating material, and wherein the wire comprises a second base alloy and a second coating material.
 5. The connector of claim 4, wherein the metallurgical bond comprises, at least in part, a region in which the first base alloy, first coating material, second base alloy, and second coating material are interdiffused with one another.
 6. The connector of claim 4, wherein the first coating material is soluble in the first base alloy, and the second coating material and second base alloy form a eutectic material system.
 7. The connector of claim 4, wherein the first and second base alloys comprise copper.
 8. The connector of claim 1, wherein at least a portion of the wire extending along the attachment interface is deformed such that a thickness of the portion is less than a diameter of the wire in the cable.
 9. A connector assembly, comprising: a first signal conductor having a first contact tail, the first contact tail including an edge having a first planar surface; and a first wire extending from a cable, wherein a portion of the first wire is at least partially flattened to form a second planar surface, and wherein the first wire is attached to the edge of the first contact tail with the second planar surface of the first wire in contact with the first planar surface of the first contact tail.
 10. The connector assembly of claim 9, further comprising: a second signal conductor having a second contact tail, the second contact tail including an edge having a third planar surface; and a second wire extending from the cable, wherein a portion of the second wire is at least partially flattened to form a fourth planar surface, and wherein the second wire is attached to the edge of the second contact tail with the fourth planar surface of the second wire in contact with the third planar surface of the second contact tail.
 11. The connector assembly of claim 9, wherein: the pair of signal conductors is a first pair of a plurality of pairs of signal conductors; each of the plurality of pairs of signal conductors has a pair of contact tails with opposing edges; the connector assembly comprises wires at least partially flattened to form planar surfaces attached to respective edges of each pair of contact tails of the plurality of pairs of signal conductors with the planar surfaces in contact with the opposing edges of the respective contact tails; the pairs of signal conductors are separated by shielding. the plurality of pairs of signal conductors are disposed in a line.
 12. The connector assembly of claim 9, wherein: the wires attached to respective edges of each pair of contact tails comprise conductors of a twinax cable.
 13. The connector assembly of claim 9, wherein the first wire is joined to the first signal conductor via a metallurgical bond extending at least partially along an interface between the first planar surface and the second planar surface.
 14. The connector assembly of claim 9, wherein a thickness of the portion of the wire is between about 75% and about 150% of a thickness of the first contact tail.
 15. A method of forming an electrical connector, the method comprising: bonding a wire of a cable to an edge of contact tail of a signal conductor along an attachment interface, at least in part, by interdiffusing at least a portion of a first material and a second material across the attachment interface to form a metallurgical bond.
 16. The method of claim 15, wherein bonding the wire of the cable to the edge of the contact tail further comprises at least partially melting the first material and flowing the first material into the attachment interface.
 17. The method of claim 15, wherein the first material comprises a first base alloy of the wire and a first coating material on the wire.
 18. The method of claim 17, wherein the first base alloy and first coating material form a eutectic material system.
 19. The method of claim 15, further comprising deforming at least a portion of the wire before bonding the wire to the contact tail.
 20. The method of claim 19, wherein deforming at least a portion of the wire comprises flattening the portion of the wire. 